If none of the above suggestions work,
go to
www.craftycomputerpaper.co.uk and order some decal film from there, scan what ever decals you have on your computer and print off a fresh set on your new paper.
That way you can do as many sets as you like and at least they shouldn't crumble so easily.....always good for back-ups.
I have used their stuff before and would certainly recommend them.
Not expensive either.
Regards......Mark.