Q. How can I remove rust stains from a concrete floor? Mrs. L. C. Hardwick Jenkintown, Pa.
A. Go to a well-stocked commercial janitorial supply store and buy any one of several commercial rust cleaners that have a phosphoric-acid base. Follow the labeled directions explicitly.
If necessary, use a full-strength application, followed by a clean-water rinse.
If no local store has the designated rust cleaner, write for one made by the ProSoCo Co., Inc., P.O. Box 4437, Kansas City, KS 66104.