I've used pure tung oil that is certified for use on cutting boards, wooden utensils and so on. It contains no driers. It works great and after a 5 or more coats with light sanding in between you can get a really nice, shiny finish.
I liberally apply one coat, leave it on the bow for one hour (during summer, indoors, with around 70% relative humidity) then wipe it down with a soft cotton rag while making sure there are no streaks or cloth fibres left on the bow. I then let it dry for one day. The next day I lightly sand it with 2000 grit sandpaper, wipe off any dust and apply another coat, repeating the process.