A razor-blade scraper is sooo inexpensive. Have you tried one?

Not yet, but I'll give it a try as soon as I buy one. Whatever
adhesive they used, it is very strong. The width of the adhesive part
is no more than 0,2-0,3 milimeters or less. But it's so impervious I
don't know that even a razor-blade will be able to penetrate it,
especially since all 4 bonds must be removed simultaneously.



re Jeff: thanks, I'll try the solvents you mentioned if a razor blade
doesn't work. Do you have any idea where one can obtain these
chemicals? I live in Europe.