washing can opener

[CiderMonkey]

Are you meant to wash can openers? Someone once told me you weren't meant to!?

[Clanad]

If you mean an electric powered one, no, certainly not the entire device.  However, the actual cutting part is meant to be removed and washed.  If it's a purely mechanical hand driven device, then sure, it's meant to be washed... and often...

[hopalong]

I use an old toothbrush with hot sopat water then I rinse then I boil it for 10 minutes

[moomoojaj]

Surely, the thought of opening a can of dog/cat food and then a can of your favourite baked beans would turn your stomach. I think it makes good hygiene sense to clean the cutting blade assembly as often as practically possible to keep the salmonella bug at bay.