Q: One visitor asked, "I installed oak stair treads on an addition and then the walls were plastered. The plasterer did not cover the stairs and plaster dripped onto the treads and stained them in various spots. Is there anyway to remove these stains? Sanding does not seem to help."

A: Sounds like water stains on your steps. If you have the right machine you can sand out these marks. They are deeper into the wood than just surface stains. The plasterer should be ashamed of himself!