Linseed oil is my choice for unfinished boards. I get the idea that some people on this board are talking about finished maple boards, and some are talking about unfinshed rosewood or ebony boards. They are completely different! As far as unfinished boards go, be aware that oil finishes should penetrate the surface, and should not be allowed to sit on top of, or congeal on the surface. This residue can get sticky when it warms up, and attract all kind of funk. Then when it finally cures, you have crud cemented onto your board. Use regular linseed oil because boiled l.o. has an ingredient that makes it dry faster, and therefore makes it harder to work with. Let the oil sit on the board for a minute or two, then remove it completely with a rag. Dispose of the rag safely so you don't start a fire. After an hour or so, buff the board with fine grade Scotchbrite (synthetic steel wool) and put the strings back on. The trick is to wipe all the excess off the board.