Removing Plaster Residue from Brick
How do I remove plaster residue from an interior brick wall?
— Kit, Toronto, Canada
Tom says: Usually, hydrochloric acid (HCl), also sometimes known as
muriatic acid, will work pretty well to remove plaster residue from
brick. Hydrochloric acid is a substance that merits a few initial words of warning, however. It is a very corrosive substance that causes severe irritation to the eyes and exposed skin. Its vapors can also cause respiratory irritation. So it's a must to make sure you have adequate ventilation, wear rubber gloves, goggles and rain gear, and follow all the instructions and precautions on the packaging. Then you're just going to have to put some elbow grease into it. You scrub it vigorously to remove the plaster, then hose down the wall. Unfortunately for you, you seem to be working with an interior wall, which poses an additional set of concerns — protecting your floor, rinsing, drainage, ventilation, to name a few. It isn't an easy problem to solve. If you do decide to try using the acid to remove the plaster, check with your
local hazardous materials authority to get additional advice on safety
and disposal. Good luck.