I’ve been looking for a good answer to cleaning unfinished wood. Yahoo answers has a good response:
For unfinished wood, the best way to clean and get all the dirt, grime, fingerprints, etc off is to use a very fine sandpaper. You can get it at any hardware store - look for 400 grit. This is so fine that it won’t leave sanding marks on the furniture, but it will clear off all the dirt and oils. Check especially down at the bottom of the piece for scuffmarks from shoes, etc and get those off, and don’t forget to clean any wooden door or drawer pulls. Don’t be afraid to put a little muscle into it if you run into stubborn marks or dirt. 400 grit is superfine, it won’t hurt anything. Once you’re done sanding, you can just wipe the piece with a damp cloth to remove any leftover sanding dust. Voila. Beautiful and ready for sale.