In the case of a stain or severe dent or scrape that won’t sand out, your only option is a patch. Patching is where we carefully remove boards using existing and newly created seams roughly a foot out from either side of the affected area. In older homes we recommend taking wood from a closet or some other area in the home if feasible to assure as close a match as possible. There are places that salvage floors and although this isn’t a guaranteed match it usually yields better results then brand new flooring patched into an older floor. However, if you’re planning on using a stain instead of a natural finish using new flooring is the most affordable option and blends relatively seamlessly.