That depends. Were they edible to begin with?
I wouldn’t eat those Kate.
If I open a bottle of pickled onions today, close the jar and return it to the refridgerator, they will be safe to eat a year from now. They’re pickled for heavens sake, in a vinegar brine. Maybe Breen’s (and others) thinking of creamed onions. Pickled onions are a mainstay of British pubs. You have them with beer or ale. Who has pickled onions for Thanksgiving ?