Not tried this myself but thought I'd pass them on
If you want a dark finish try ebonizing the wood. Take steel wool and let it sit on white vinegar for about a week. Take the vinegar and run through cheesecloth to remove steel bits. Wipe on wood and it will blacken it like ebony, but grain will show through. Clear coat or shellac over that. Stunning appearance.
Also if you've stripped a screws head try this it may work for you.
Thanks
Kimball