For those concerned about going into polishing with a TDE, here is a simple test. This should be done only with the final abrasive before polishing. Clean and dry the mirror and tool. With a waterproof marker, make a tic tac toe like pattern on the mirror, going all the way to the edge. Then do a short wet, maybe 30 seconds or a minute with at least a full rotation of mirror and too. Check the wear of the pattern. If it is wearing away gradually all around, all is well. If everything is wearing except the edge, you have TDE. If the center isn't wearing, the mirror has a hole in the center. Either condition should be corrected before proceeding to polishing. This was shown to me as "The Pencil Test", since a pencil works as well as a permanent marker. Hope this is helpful. RICH