Furniture, Wood and Cabinetry Finishing - How do you get unknow stains out of oak?

I'm in the process of refinishing an oak table and it has "unknown stains" on it. One is black and the other one might be grease. I put two layers of stripper on it and it didn't really come off.

If sanding the stains don't work, any suggestions?

Bonnie

Attack the 'may be grease' stain first. Put a liberal applicatoin of talcum powder over the area, wet it down with paint thinner and let dry.

Brush out the area with a stiff bristle brush. Repeated applications may be needed.

The black area is probably a water mark. It can be lightened, if not totally removed, with oxalic acid, available from your local paint store. Do the entire top for uniformity.

Hi Bonnie, If your table top is solid oak and not veneered, there are a couple things you can try. First, I've used liquid (not the thick stuff) toilet bowl cleaner and have alot of success on water stains and ink stains, but you must wear rubber gloves and safety glasses in a well vented area, if it's a real tuff stain I also use a "wire steel" brush. And then when yor done, nuetralize with alot of water. Second, if that doesn't work, and you're sure it's a solid oak top......you can use a belt sander with 60 to 80 grit paper, but you really have to know how to use it or you can ruin the table top! and you have to sand the whole top evenly, which can be alot of work....If you don't know how to use one, don't attempt it, find someone who knows how!! good luck