In reply to Rog Wilko:
I've been dropping off similar types of cells (LR44 and so on) in the recyling bin at Robert Dyas.
There's a potential issue of the design (extended metal outer cover) causing short circuits in other batteries if you have enough of them mixed in with all the other AAA/AA/C/D/etc cells, which is a fire risk.
So, yes, leave them in a small plastic bag, or something.