Polish are easy. Sand off any imperfections. Heat the grip with whatever is convenient; heat gun, hair dryer or the sun on a hot day. Wipe off the oil as it oozes out. When you get tired of doing this, wipe it down with denatured alcohol. Now rub it down with Kiwi Cordovan (dark maroon color) shoe polish (the stuff in a round tin). Then buff it a little. The basic idea is to get enough oil out to allow some of the shoe wax to soak in. The shoe wax seals the surface, darkens the wood a little and gives it a soft luster. You wont believe how good it looks and feels. Original, only better. I would post a picture, but it wouldnt do it justice. You have to see and feel it for yourself. Takes 30 minutes, tops.
It is also very forgiving. Handling marks dont show. If you get a surface scratch it is no big thing. Just sand it lightly and put on some new wax.
And hey, if you dont like it when you are done, you can still go through all the BS with strippers, dyes and polyurethane etc.