Someone recently asked about sanding floors in an old house. He was worried about losing the patina and damaging the wood. I asked historic architect, Doug Harnsberger (with John Milner & Assoc.), who's worked on many important restoration projects. Doug says: "I imagine that the owner has had experience with large, professional floor sanding equipment that can remove the age and patina of an historic floor far too readily. With 200 year old historic floors I'd go easy on the sanding - probably approach it by hand sanding if feasible - it would depend on the circumstances. For Greek Revival era floors I'd recommend using an "open" tung oil finish rather than a "closed" polyurethane."