Vintage 1991 Campbell’s soup insulated mug set 4

Set up for Campbell’s soup M’m M’m Good insulated mug set of four. These have been around the family forever so I’m estimating 1991. They are in Very good condition, 2 have some slight inside yellowing from age are use one of the inside papers that look like it had once gotten wet. No cracks or breakage just some scuff marks. I believe these for a promotion when cuppa soups were the big thing. Made by Royal Crest.