Furniture, Wood and Cabinetry Finishing - Need advice on how to restore the top of a walnut Danish Modern Credenza

I am seeking advice on how best to restore the top of a walnut Danish Modern Credenza which I recently purchased at a yard sale. There are some white rings that shouldn't be too problematic; however, there are some dark stains in the veneer. I have no idea what they are, but I'm wondering how best to minimize their appearance. I have posted pictures of this piece on Photobucket.com which can be accessed through this link by pasting it in your browsers address bar.

http://s98.photobucket.com/albums/l261/Fiestababy/

Thanks in advance for any suggestions.

ReBecca

Have you ever tried Formby's refinisher? I have used it several times with good results. It is pretty quick and it is less stressful on a veneer than stripping it. It works by 'melting' the old finish and reapplying it in one step. The directions an the packaging are pretty straight forward. And you can get it at your local home improvement store. When it is dry you may want to protect with a good top coat.

My brother restored the damaged areas on the top of the credenza which I had purchased at an Estate Sale. Thanks so much to "remodelfool" for recommending Formby's Refinisher. I couldn't find this brand anywhere and one hardware store had to special order it for me. My brother used it and was very impressed with this product. The damage to the top of the credenza was pretty bad and the results were more than satisfactory. If I weren't feeling so lazy, I'd take pictures of the end result to show the improvement. Much thanks!