I have a well loved and well used Canon 550D. This has lost a couple of mostly inconsequential bits of rubber over the years, but recently the thumb rest has come off:
Most importantly, this is a bit annoying but also having some extra open holes into the camera isn't going to improve the weather resistance if it does get out in the rain. Fortunately the thumb rest fell off into my camera bag so I still have the bit of rubber. The question is what should I use to reattach it?
Trivially available I have generic woodworking glue, rubber solution as used for fixing patches to bicycle inner tubes and a variety of not very sticky glues you would expect to find in a house with young children. If it weren't for the little holes (through which copper can be seen), I'd use the rubber solution but I'm just a little bit paranoid about getting sticky stuff into the critical internals of the camera. I suspect the answer is "use the rubber solution and be careful", but I also think it's worth checking first...