A few of my Dragonara Palace chips have a clear rubber adhesive on them. I suspect someone long ago may have glued them to a display board as the adhesive is only on one side of each of three chips. I've tried all sorts of picking, peeling and rubbing to try and remove it. I've gotten some of it off, but there are still bits and pieces, as well as a thin transparent film covering parts of the hot stamp in the middle. I suspect it's going to require some type of chemical cleaning, but I don't want to just experiment. Anyone have any ideas as to the best products to try first that won't damage the hot stamps or the chip itself. Maybe non-acetone NPR? These are very old - from the late 60s to early 70s. but otherwise in excellent condition. Produced by BC Wills.