I had some paint overspray on the one I got. It looked like someone painted an object on the table and didn't have enough protection on the table to keep all the paint off. Anyways I took some 0000 steel wool and dipped it in lacquer thinner and gently rubbed it out and it came right off.
Make sure you rinse the top real good with soap and water to get all the thinner off so it doesn't attack the plastic. Then do like Bob said use some mineral oil and rub that in as the thinner will dry the plastic out.