I have a concrete porch that was painted 40 years ago..paints o.k. have to live with it. There's quite a buildup of water deposits on it. Any suggestions on how to dissolve them? Tried paint remover..doesn't work. Used Hydrochloric acid on a portion...it works but wow...the fumes and clean up is pretty terrible. Tried vinegar soak..works pretty good except there's alot of scrubbing involved. Any easier suggestions?