I have heard of other folks using Danish oil, tung oil, or just buff and wax. I use sanding sealer, after wiping with rubbing alcohol (to take some of the oils from the surface and let the sealer bond) because it is the only product I have tried that dosen't build up on the surface but seals in the oil that otherwise turns your hands black. Any built up surface finish such as urethane or laquer will eventually bubble and flake when the natural oil eventually de-bonds it.