On Sunday, August 16, 2015 at 10:00:12 PM UTC-5, J Burns wrote:

I like WD-40 for cleaning gunky can openers. It would hazardous to
inhale but is evidently harmless to ingest in trace amounts. I wonder if
it does any harm by driving out lubricant. Why don't can openers have
Zerk fittings!

I have 2 old Swing-A-Way (they got the name from the wall mount model). I remove the cutter disk and clean the entire opener in soapy hot water, then lube the mechanism with peanut oil.