I will report back when I have gotten somewhere.   I was going to ask what is White Spirit, but apparently it's contraband.   I have no 'essential oils' lying around the house.   I'll try seeing if the top layer will start to peel with a knife, then may give it a go with mineral spirits or acetone and a scrubber. I know goo-gone works with enough rubbing but I'm afraid I'll have to get the paper layer off first. So, I'll work through the list above until something gives.

Anyway, be patient, it may be a few days before I can report back. Again, thanks, and thanks for not making fun of the sand collection!