I removed a skin from Sopiguard on a 12.9 MK, and it left a little residue that was easy to remove with an isopropyl alcohol wipe. Some of the skin vendors even provide instructions about how to safely remove the skins. There are numerous videos out there about how to do it too. It’s not hard at all.Did you ever have to remove it? If so what was that like and did it leave any marks?
The online vendor to whom I sent it to sell agreed it was in excellent condition.