Removing stains on limestone?
August 6, 2024 7:54 AM Subscribe
I stained my limestone front steps with cork-based "coasters" for flowerpots. How to remove?
I stupidly used cork-based mats or coasters underneath flowerpots on my new-ish limestone steps. I soaked the cork beforehand to try to stop staining, but it didn't work and the coasters left brown circles on the stairs - like big coffee cup stains. The stains are about 2 weeks old. I tried powerwashing and some different household products, which removed some of the staining, but maybe like 50%. The most effective thing seemed to be Softscrub, which has bleach. I am worried about ruining the stone with too much bleach or acid or whatever. The stain is definitely in the pores of the stone - i.e., the powerwasher does not take it off.
After some research on the web, I have three methods that I and thinking about trying: (1) a homemade poultice made from baking soda and 12%-strength hydrogen peroxide, which you are supposed to leave on the stone for 24 hours (I am worried about overbleaching though); (2) a professional stone cleaning soap made by Black Dimond; or (3) leaving on the Softscrub for an hour or so before rinsing it off - the Softscrub seemed effective before, though it also seems harsh.
Any thoughts on these methods or others? Thank you!
I stupidly used cork-based mats or coasters underneath flowerpots on my new-ish limestone steps. I soaked the cork beforehand to try to stop staining, but it didn't work and the coasters left brown circles on the stairs - like big coffee cup stains. The stains are about 2 weeks old. I tried powerwashing and some different household products, which removed some of the staining, but maybe like 50%. The most effective thing seemed to be Softscrub, which has bleach. I am worried about ruining the stone with too much bleach or acid or whatever. The stain is definitely in the pores of the stone - i.e., the powerwasher does not take it off.
After some research on the web, I have three methods that I and thinking about trying: (1) a homemade poultice made from baking soda and 12%-strength hydrogen peroxide, which you are supposed to leave on the stone for 24 hours (I am worried about overbleaching though); (2) a professional stone cleaning soap made by Black Dimond; or (3) leaving on the Softscrub for an hour or so before rinsing it off - the Softscrub seemed effective before, though it also seems harsh.
Any thoughts on these methods or others? Thank you!
Response by poster: Will try later. Picture a coffee mug stain - brown, heavier on the outside perimeter, lighter inside that circle. About 8 inches in diameter.
posted by Mid at 2:42 PM on August 6
posted by Mid at 2:42 PM on August 6
Response by poster: Answering my own question in case anyone one day stains their limestone with cork (hah), the baking powder/peroxide paste seems to be working. I have applied it 2x and it has removed much of the stain. I got 12% peroxide on Amazon and mixed it into a paste with baking powder, spread the paste on the stain, and let it sit for about 20 minutes. I found that pushing the paste around with a sponge - i.e., kind of pushing it into the pores of the stone - seemed to be helpful. The stain is reducing and the stone does not (at least yet) seem damaged. Some of the online stuff says that you should leave the paste on for 24 hours with a plastic wrap covering to keep it moist - I haven't found this to be necessary, at least yet.
posted by Mid at 6:11 AM on August 12
posted by Mid at 6:11 AM on August 12
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posted by nouvelle-personne at 12:05 PM on August 6