Is it possible to remove grout/cement stains from an old tub?

January 31, 2017 7:26 PM

I'm retiling a tub enclosure. Baring the tub revealed stains on the tub enamel from the old cement/grout. Our tile guy would like to re-tile the tub exposing some of the previously covered up tub enamel. We don't want to re-enamel the tub. Is there any products you suggest we use to try to remove the old grout/cement stains? He suggested we try foaming oven cleaner.
posted by arnicae to Home & Garden (1 answer total)

If this was conventional grout, held together with Portland cement (i.e. not epoxy), and assuming that the stains are just Portland cement residue rather than a pigment that was mixed in, then you want a fairly potent acid. Portland cement is vulnerable to acids, but alkaline cleaners (like oven cleaner) won't touch it.

In the tiling section of your home improvement store you'll find a mild acid cleaner called "grout haze remover," but it's probably not potent enough. Grout haze removers are meant for cleaning up new installations that are not fully cured, and is weak to make it safer and to reduce the chance that it will hurt the new grout lines. You're going to need something stronger. I'll stop there, because I'm not an expert on acid cleaners and their use, but oven cleaner is the wrong stuff.
posted by jon1270 at 5:39 AM on February 1, 2017