Once you have cleaned the stock down and given it a sparing rub with boiled linseed oilicon and let it set for a day or so, I find that a coat of Renaissance Wax will protect the oil finish, and prevent drying out.

This wax was developed for museum use and has been designed to do no harm to whatever it is put on. It can also be used for coating metal surfaces and provides good protection from fingeprints and dust damage.

Renaissance Wax is produced in the UKicon by a company called Picreator, but is fairly easy to obtain worldwide via Amazon..