I have used "Plasti-tac" for many years when I used to display.  It's white and
I found it in a Stationery store.  you stretch it several time to activate it
and then put a small piece on the shell, as it cools it holds tight.  I remove
it by use a another activated piece rolled back and forth across the shell.  The
blue stuff colors the shell.  Plasti-tac doesn't work well if you have excess
oil on the shell.  It will break down over time..

Bob



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