Blue-Tack (as we call it this side of the Atlantic) works fine for
relatively short periods, but do NOT leave it attached to shells for long
periods - by long I mean over a year or so.  I kept some labels attached to
shells and eventually the sticky degenerated into a much softer mess, which
did not come off in one piece.  It is therefore a nightmare getting lots of
little bits of sticky out of fine detail of shells.

In future I will only ever use this stuff for temporary fixing - for
displays, etc.  I will not use for long term fixing, although I do not have
an alternative that is as easy to use.

Tom Walker
Reading, England