Cleaning Seal Jumbo 150 I just acquired a nice hot dry press, Jumbo 150 by Seal. I do need to clean the upper surface (not the very top with a knob and lights but the inner part that comes in contact with prints) of dried up glue (or something). To me, it looks like just a smooth sheet of aluminum. Is this part coated with anything? The dried up gunk is brittle but stuck well and covers very large area. What's a good way to clean this? I just don't want any old abrasive in fear I might take off some coating or damage it in some way.