I used to buy these old fashioned food covers at UK Jumble Sales or Boot Sales, they were sold for almost nothing. I'd buy every one I saw; I imagine they are from the 1950's.
These days they would probably be classified as 'Kitchenalia' and have crazy price tickets.
They've just been given a refreshing coat of 'Wimbledon Green' spray paint, and are ready for use again.
No Wasps on my Ham Sandwiches, or my slice of Battenburg Cake; thank you very much!