Slippery Rock Gazette

Part 3 – Removing Stains from Quartz Countertops

Karin Kirk

usenaturalstone.com

Photos and Charts by Karin Kirk, Natural Stone Institute

For those readers just joining the conversation, the first and second installment of  Karin Kirk’s article Do Engineered Countertops Stain? can be found in our August and September issues, also available on www.slipperyrockgazette.net.

The third round of testing aimed to find out which happened first: removal of stains or damage to the surface. I experimented with a variety of cleaning approaches to see what worked.

Permanent Marker Stains

The most persistent stain was the permanent marker, so I first focused on removing that.

Scrubbing with abrasives lightened the stains but didn’t remove them, except on darker colored samples where the stain faded enough to become invisible.

In the meantime, scrubbing with abrasives damaged the finish, while still not removing the stain.

Non-acetone based nail polish remover erased the stain and did not appear to damage the finish.

Above, left: On the left side, turmeric left a faint yellow stain on Viatera Celeste. On the right side is a very faint red stain from hot sauce. Chemical agents like bleach and nail polish remover test as more effective than scrubbing with abrasive pads or cleaners. Above, right: Caesarstone Nougat with moderate stains from pink (upper right) and blue (lower right) food coloring. There is also the remnant of the letter F written in permanent marker.

Food Dye Stains

Stains from food dye were unresponsive to scrubbing, so I moved on to other methods. Some quartz manufacturers advise against using bleach, while others recommend it. Thus, bleach seemed like a worthwhile cleaner to test—in the name of science, of course.

I used a small amount of undiluted bleach and the scrubby side of a Scotch-Brite kitchen sponge. This lightened the stains in all cases, but didn’t remove them completely. Interestingly, the stains faded overnight and were less visible the next morning. 

In one case, with Viatera Celeste, the stain was completely invisible the next day. On the other samples, the stains were very faint the next day. 

This is consistent with information on the Silestone website, which says that bleach can continue to affect their products for 12 hours after application.

Nail polish remover didn’t noticeably lighten the food dye stains. All in all, these stains were the most persistent and difficult to remove.

Food coloring was among the most pervasive staining agents tested. Other staining agents tested included turmeric, hot sauce, Sharpie permanent marker, grape juice and oil.

The Bottom Line

Engineered quartz is more tolerant of chemical cleaning than physical cleaning.

Cleaning can be thought of as either a mechanical process or a chemical one. Scrubbing action and abrasive materials do their jobs by physically scraping the stains away. The quartz manufacturers’ warnings are correct. Using abrasive cleaners or scouring pads will likely remove the softer portions of the material—the polyester resin binder. Thus, one needs to weigh the need to remove a stain with the likelihood for damaging the surface.

Bleach and nail polish remover work because of their chemistry. That is, they dissolve or react with the stain to make it rinse away or fade to the point where it becomes invisible. These methods worked better than abrasives and did not appear to impact the samples. But in the case of food dye, even full strength bleach still wasn’t always successful in completely cleaning the surface.

Damaged finish from kitchen sponge and Bar Keeper’s Friend (rough patch, left center) on this Cambria Templeton sample.

One More Caveat

Even though this was a fairly extensive test, I didn’t try every combination of staining and cleaning on every color—that would be an enormous project. Furthermore, there are numerous variables that are not practical to control. Slabs vary from batch to batch. Colors and patterns change over time. What some users might call “vigorous” scrubbing, others might consider over-the-top. 

There are many brands of sponges and scrubbers, and several variants of a given type of cleaner.

These tests offer a general idea of how engineered quartz products hold up, but far and away the best thing to do is test the materials that are relevant to you.

As always, the more you learn, the better. Every surface material has its limitations, no matter if it’s natural or synthetic, common or rare, expensive or economical. If a sales pitch sounds too good to be true, it probably is. While boastful claims make for a compelling marketing narrative, customers are wise to double check and look deeper whenever possible.

In practicality, no material is literally maintenance-free. Every surface, including engineered quartz and natural stones like granite, marble, and quartzite, need to be cared for in a manner that is compatible with its properties. The trick is to understand the properties and be an informed consumer. Just as I advise a science-based approach to shopping for natural stone, I encourage the same curiosity when considering other types of materials, too.

Karin Kirk is a geologist and science educator with over 20 years of experience. She has taught college level geology, online courses and organized field trips. She currently works as a freelance science writer and education consultant. She brings with her a different perspective to the stone industry. Karin a regular contributor to usenaturalstone.com and the Slippery Rock Gazette.