Transparent crack filler?

[Cooler]

When I had my picture framing shop I had tins of colored wax that we used to fill nail holes or clean up miters.  They make them in tins and in sticks in an amazing array of colors.  I had about 20 colors and I was always able to make a good match.

I would just scrape a bit out of the tin with my finger (it is pretty soft) and rub it in the nail hole or gap in the miter and wipe off the excess with a rag.

http://www.grignonsart.com/pictureframin...iller.html

[Steve N]

A dark wood like Kingwood with a flat/satin will highlight a lot less than a Blond wood with any finish, where the pale woods who may even start starkly white will yellow pretty uniformly. If you want a finish, try it on a piece of scrap.