As far as coins (and bills actually) of the pre-EURO era in Europe are concerned you can still donate them to UNICEF (similar like the change for good program) via Euromoney24
Dutch guilders, German mark, Slovenian tolar, Austrian schilling, Portugese escudo, Spanish peseta, Belgian and Luxembourg franc, Maltese Lira, Irish pund, Koruna of Estonia and Slovakia - that might be a nice way of using them. Only portage cost is the actual donation, because you can`t really use them anymore.
official reference:
http://www.unicef.at/unternehmen.html - or see google translation as it is german
