I got my daughter a light oiled show halter for 4-H. It's palamino colored and while she won't care because she thought she wouldn't get one this year, I'd prefer a darker one. Is it possible to use a darker oil and change the color a little? I don't want to ruin it and she'll be happy with whatever color she gets, but if we could make it darker it would look better on the paint she's using. What kind of oil should we use?