My late step mother had a mania for collecting just about every plastic tub she could get her hands on! These included stacks of old margarine tubs, Ovaltine containers, and every size and shape of Coleslaw pot, Yogurt tub, Coffee and Jam Jars, and even pots from Nivea face cream!
After she passed away, her collection, mostly filled with bits of leftover food, or Blackcuurants from the freezer, were enough to fill a large lorry skip on their own!
Some of the containers where obviously decades old, and had become brittal with age. She would sometimes present any visitors who had called with a gift of one of these containers as they left, most of which I presume went straight into the nearest Bin, the contents unfit for Human consumption!