How to Clean a Composite Sink and Remove Stubborn Stains

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With the variety of kitchen sinks available, from more common materials sinks such as stainless steel and cast iron to the more exotic materials such as copper and marble, no matter the material, every sink has its positives and negatives.

You may have seen it in a catalog or come across it on the internet, but what is a Composite Sink? 

In the article, we will look at how a composite sink is made and the pros and cons of owning one of these sinks, and, of course, how to clean a composite sink and, specifically, what not to use.

What Is a Composite Sink?

Ruvati 30 x 18 inch Granite Composite Undermount Single Bowl Kitchen Sink - Midnight Black - RVG2030BK

Composite sinks are popular and desirable because of their durability and low maintenance. They are engineered by combining acrylic resin and other hard minerals like granite, stone, and quartz. The sink is created by placing the blend in a sink-shaped mold and left to cure.

Made under high pressure, they are hygienic, nonporous, and resistant to heat and chips. Made with 70-80% stone, with the remainder being fillers, these sinks are generally more durable the higher the stone content.

Sinks constructed solely from stone are not as hygienic and can harbor bacteria quite easily. This is why acrylic resin is added, not only to make the sink easier to clean but the resin helps to fill the small holes that the stone leaves behind.

Available in both a matt or polished finish depending on the manufacturer, these sinks range in color from bright yellow to matt black and are also used as a design feature in contemporary kitchens or baths.

Composite sinks are of great value as they are cheaper than solid stone sinks and slightly more expensive than steel sinks. They are arguably more eco-friendly thanks to their manufacturing process and lack of a need for daily cleaning with polluting chemical products.

The Pros of Installing a Composite Sink

Lordear 31×18 Inch Quartz Undermount Kitchen Sink 31" Kitchen Sink Granite Composite Metallic Black Deep Single Bowl Kitchen Sinks with Accessories

Here are some advantages of having a composite sink.

  • Durability – composite sinks are durable, hard-wearing, and relatively low maintenance. The sink is resistant to scratches, chips, and dents from normal daily use.
  • Maintenance — this sink material is generally very easy to maintain and keeps looking clean and like new. In everyday use, you need a little washing-up liquid, warm water, and a soft scrub sponge that will keep the sink clean.
  • Heat-Resistant — composite granite sinks are known to be somewhat heat-resistant. A moderately hot pan won’t leave a mark unless they’re allowed to sit in the sink for more than a minute or two.
  • Aesthetics — composite sinks are made from a blend of materials and can be matched to other design elements in your home more easily. 
  • Safety — Some people are worried about the small amount of radon that granite countertops may emit. But this is not a problem with composite sinks because the stone is mixed with a polymer. Plus, unlike granite countertops, composite sinks don’t need to be sealed periodically.
  • Sound — composite sinks reduce noise in the kitchen thanks to their ability to absorb sound from the garbage disposal or the sound of pots and pans being handled in the sink.
  • Price – composite sinks are less expensive compared to solid granite sinks while still allowing for the benefits of having the aesthetics of a granite sink with fewer drawbacks.

The Cons of Installing a Composite Sink

Here are some things to look out for if you’re going to install a composite sink.

  • Heat-Resistance — composite sinks are heatproof, not 100% heat-resistant. The resin used to bind the stone can melt if extreme heat is applied. Ideally, avoid placing a hot pan or pot in the sink for more than a minute or two. 
  • Weight — composite sinks weigh more than some other types of sinks. This means that you might need to use additional support when installing a composite sink.
  • Unforgiving — composite sink material is much tougher and thus much harder.  Plates, dishes, and glassware, if dropped, will break, similar to dropping anything on a stone counter.

Possible Granite Sink Problems

Kraus Quarza Kitchen Sink, 33-Inch Equal Bowls, Black Onyx Granite, KGD-433B model

Composite sinks are difficult to stain permanently. This is a good thing because it means that the sink will stay clean.

However, some oils and acidic foods may seep down into the surface and cause a stain. If you wipe up a spill as soon as possible, there is less chance that the stain will become permanent.

Permanent stains with composite sinks can easily be avoided by following the steps below.

Hard Water Stains

Typically, these stains are a build-up of minerals found in hard water rather than soft water. When using the water faucet, try to vary its position so that the stream doesn’t always pour in the same place. A better solution still is to use a water softener in these very hard water areas.

Soap Scum And Mineral Deposit Build-Up

Repeatedly leaving soap residue in the sink will eventually start to create marks. Especially if you are in an area that has hard water, ensure that these stains are immediately cleaned and not left to sit. 

Food Stain Build-Up/Stubborn Stains

Mild soap and a daily cleaning regimen is the best way to avoid stubborn stain build-ups. Repetitive use of the sink on one side will increase the chances of stubborn stains from food deposits. Certain foods can cause more staining than others, beets or acidic fruits.

White Cloudy Haze And Marks

Bleach-based cleaning products and ammonia are too abrasive and will leave a cloudy white hazy layer on the sink’s surface. Avoid leaving acidic foods, juices, or coffee lying in the sink for a long. Flush them with water as soon as possible.

What Not to do When Cleaning a Black Composite Sink

Ruvati 33 x 22 inch Drop-in Topmount Granite Composite Single Bowl Kitchen Sink Slope Bottom - Midnight Black - RVG1033BK

When cleaning your composite sink, it is best to know what to avoid. Composite sinks are very durable and will last you years if you take care of them and know which cleaning products to use and which ones to avoid. We will cover a few things that you should use if you have a black composite sink.

Abrasive Scrubbers

Brillo pads and steel wool are great cleaning solutions for many types of sinks. However, for a composite sink, you should use much gentler products. Rough and abrasive scrubbers can easily damage the sink and leave behind many tiny scratches.

Instead, use a soft cloth, like a microfiber cloth, that won’t damage the sink or leave scratches behind.

Harsh Cleaners

Harsh cleaners have extremely strong chemicals that will damage the sink so avoid these at all costs. They will not only strip away the shine but can permanently damage the sink.

Limescale Removers

It may be tempting to use limescale removers for their convenience and as advertised properties. Most people believe that the watermarks in their sink can be eliminated with this product.

However, the truth of the matter is that these commercial limescale removers are way too strong for composite sinks and may end up leaving large discoloration marks and damaging the sink.

How to Clean a Composite Sink

Lordear 31×18 Inch Quartz Undermount Kitchen Sink 31" Kitchen Sink Granite Composite Metallic Black Deep Single Bowl Kitchen Sinks with Accessories

Having outlined the things to avoid when you clean your composite sink, it’s time to cover the best ways to clean the sink and make sure it stays looking as good as the day it was installed.

Essential Items

Here is a list of the necessary items you will need to proceed to clean your composite sink.

  • Sponge
  • soft-bristled brush
  • Mild dish soap
  • Baking powder
  • Vinegar
  • A soft cloth (microfiber) or paper towel
  • Hot water
  • Soft cloth

Clear the Sink

Before you start cleaning, take everything out of and around your sink. Make sure to remove all the dirt and garbage inside and outside the sink before you start cleaning it.

Use Hot Water and Mild Soap to Scrub the Sink

To clean everyday mild stains or stains left by washing up liquid from your composite sink there’s a very simple way to remove these without the need for abrasive chemicals.

To clean your sink, mix hot water and soap in a bowl. Use a soft scrubber to scrub the entire sink. Rinse it with warm water until it is clean. Dry the sink with a kitchen roll or microfiber cloth.

Apply Baking Soda

To remove stains from a composite sink, there’s nothing like baking soda. Drizzle some baking soda on any stained areas and leave it for a minute or two to soak in. Then scrub it with a soft cloth or sponge.

Baking soda is typically coarse and can clean the surface leaving no marks or scratches. Once you can see the marks have disappeared, wash the sink down and make sure to dry the sink.

Apply White Vinegar

White vinegar and baking soda work very well together in removing hard water stains. When they are mixed, they start to bubble up. Then, use a brush like a toothbrush to gently scrub the vinegar and baking soda mix wherever you see white marks.

You may need to pass over a couple of times to completely remove the marks, but once you are finished, wash your sink with water and then dry it. Make sure to dry your sink after every use so as to not allow the hard watermarks to ever return.

Removing Metal Scuff Marks From Pots

To remove stubborn stains and silver marks left behind by metal cookware, use ‘Bar keepers friend’ or ‘Cif’ cleaning cream and a stiff nylon brush or nylon scrubbing pad. Apply a small amount of Cif cleaning cream to a nylon brush and gently scrub the area with metal scuff marks.

To use ‘Bar keepers friend,’ apply a small amount onto a scrubbing pad and add a little water to the pad to create a paste. Using the scrubbing pad, gently scrub the marked area to clean.

Once the marks have been removed, wash with clean water and then dry the sink.

Restore Its Shine with Mineral Oil

After you clean and dry the sink, there is just one more thing to do. These sinks are really beautiful; however, if they are not maintained, they can start to look old and dull. We will remedy this by gently polishing the sink with mineral oil. Dip the edge of a dry cloth in a little mineral oil and rub it in evenly until the entire sink has been covered and is gleaming.

Try and repeat this process about once a month, and your sink will keep its beautiful shine for years.

How to Clean Stubborn Stains from the Composite Kitchen Sink

Cleaning stubborn stains on a composite sink may feel difficult, but using the following steps will make things easier.

You may either have ingrained food stains. In this cleaning guide, we shall look into how to clean both types.

Required items

  • Whiting powder
  • Hydrogen peroxide
  • Plastic wrap
  • Soft cloth or sponge

Steps to Clean the Sink

  1. Following the instructions provided with the whitening powder, mix the hydrogen peroxide and whitening powder, to form a thick paste.
  2. Apply the paste to the stained area in the sink, making sure to only apply enough to create a 1/2-inch thick layer over the stained area.
  3. Once the stained areas on the sink are covered with the paste, use plastic wrap to cover the applied paste. The sink should stay covered with plastic wrap for a day or two (24 – to 48 hours), to get the desired results.
  4. Remove the plastic wrap from the sink. Check if you have the desired cleaning results on a small area before you remove all the plastic wrap. Then use a soft clean cloth or sponge to wipe all the paste off the shink.
  5. Once all the paste has been wiped off, use clean water to rinse the sink and then dry the sink with a clean cloth.

How To Remove Hard Water Stains

Dirty Sink

Hard water is a problem faced by many homeowners. Without testing your water with any tools, you can easily tell if you have hard water when there are a lot of watermarks left over from dried standing water. This is mainly due to the water in your area containing a high mineral content.

If you have dried water marks on your composite sink follow the steps below to make sure you clean them without damaging your sink.

Required items

  • Hot water
  • Sponge with a scrubbing pad
  • Mild dish soap
  • Mineral oil
  • Soft cloth

Steps to Remove Hard Water Stains

  1. Using a mix of either warm water and a little white wine vinegar or dishwashing liquid, scrub the sink with a light scrubbing pad.
  2. Continue to scrub the affected areas of your sink until all watermarks are clean.
  3. Rinse the sink with clean water.
  4. Dry the sink using a clean cloth. It may now be clean, however, to ensure it stays this way it needs to be dry of any standing water.
  5. Once dry you can easily restore its luster by applying a little mineral oil to a cloth and rubbing it all over the clean sink. Allow it to sit for a few seconds and then wipe off the excess to get that new-looking shine.

Items Which Can Damage a Composite Sink

Even though composite sinks require pretty much the same care as stainless steel or ceramic sinks, below is a list of things that can damage colored composites.

Avoid any and all of the things in the list below to ensure your product is still covered by the warranty.

  • Spray cleaners e.g Oven cleaners
  • Bromine, chlorine and iodine used in photography development
  • Bleach or bleach based cleaners
  • Harsh or coarse cloths and creams
  • Commercial descaling liquid
  • Dyes e.g Clothes, hair and food
  • Cleaners with ammonia
  • Aggressive cleaning products
  • Steel wool pad on the sink surface. Small pieces or hairs that break off while cleaning pots will leave rust marks in the sink
  • Varnish or varnish remover
  • Be careful when washing pots as they will leave scuff marks on the surface


Composite sinks are very low maintenance and extremely durable. As shown above, the process is easy–all you need is some hot water and dish soap!

Looking after your sink by daily cleaning is the easiest way to prevent any really stubborn long-term stains. Mineral deposits can form very quickly, and this can cause discoloration. A colored sink will show off white spots or stains and make the entire room seem dirty and the sink unattractive.

Being proactive and spending a few minutes each day gently cleaning the sink can prevent this and ensure that your sink always looks clean.

Hopefully, you can now make sure your precious investment stays looking as good as the day you bought it for years to come.

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