I installed 100 sq ft of mosaic tile on a floor without cleaning excess mortar as I went. Now I have what seems like 10,000 grout lines that all need to be cleaned. Any advice or suggestions on how to clean them? How clean do they need to be?
Make a weak acid solution using Muriatic Acid (pool acid) and water in a 5 gal. plastic bucket, 1 cup:gallon. Using gauntlet type chem gloves and eye protection, scrub with acid. Use a grout sponge to rinse and wipe clean, using clean water and wringing frequently. Repeat until all excess mortar and haze is gone.
Note: above method is effective for removing dried smears and haze, solid clumps of dried mortar must be mechanically removed (scraped).