“I had a concrete porch installed. When the painters sprayed a fresh coat of paint on the decorative railing, they got black paint on my new concrete in the outline of a large piece of paper. They and I don’t know how to remove it. Can you find me anything that will take the paint off?” The Newton Falls Public Library staff could see where a clean patch outlined in paint in the center of a new porch would not be appealing.
Clois E. Kicklighter, in Modern Masonry: brick, block, stone, warns that “faulty cleaning techniques or the use of the wrong cleaning agent” can ruin the appearance [p.127]. For brick and concrete block he mentions cleaning with an acid solution or sandblasting, as well as rubbing it with a smaller piece of block. This is especially useful for removing mortar. We weren’t sure if these methods would be effective for removing paint. Masonry Basics, which is part of Ortho’s All About series, deals with removing paint and graffiti stains from brick. It suggests pressure washing, scraping with a wire brush, scrubbing with a mixture of trisodium phosphate (TSP), semi-paste paint remover, spray paint remover, muriatic-acid solution, or the final option sandblasting [p. 91]. Again, we weren’t sure if these would be effective on concrete.
Rodale's Book of Practical Formulas has some formulas for general concrete cleaning, but none for paint removal. Fix It, Clean It, and Make it Last: the ultimate guide to making your household items last forever by Gayle K. Wood addresses the problem of oil and grease stains on concrete. Wood recommends covering the area with mineral spirits or paint thinner. Then spread cat litter, sand, baking soda, or corn meal over the spot. Leave it for at least 12 hours and sweep it up [pp. 251-252]. Since you are removing stains with a substance commonly used for removing paint, this seems to be a possible solution to our patron’s problem.
The expert online at the Paints and Coatings Resource Center [www.paintcenter.org] offered several suggestions for removing paint from a concrete driveway: “scrape or wire brush the paint off the surface . . . maybe a wire wheel brush on the end of a cordless drill . . . would be much easier than scrubbing manually . . . you might be able to use as paint stripper that you can purchase from a hardware store.” These instructions, like all the others previously mentioned recommend testing in a small obscure area first. Our patron is going to take these suggestions to her mason to see if one of them may work for her problem.