Furniture, Wood and Cabinetry Finishing - Greasy spot on unfinished wood

I have an unfinished table (probably walnut, but I'm no expert) that I would like to finish. However, time has left two or three "pizza box" stains in the wood. Do I need to remove the greasy spots before attempting to finish the table and if so how would I go about doing that? Someone recommended Murphy's Oil Soap but the directions on the bottle clearly state not to use it on unfinished wood. Can anyone help? Thanks. A reply to my email (dapeg1@adelphia.net) would be appreciated.

Use mineral spirits and a clean, white cloth. Dampen the cloth with the mineral spirits and scrub away the oil/grease. Mineral spirits should cut the grease. It won't leave a residue when it evaporates. Wipe down the piece with mineral spirits before staining to reveal other such contaminants as: glue, handprints, and other places that will interfere with staining.

Hope this helps.

Thanks for the help. I'll give it a shot! :)