The “Ready to Serve” Heinz kidney soup still bears its original price sticker and would cost 10d, meaning it was sold before decimalisation in 1971.
The Green Giants niblets corn cost eight pence, according to the package design.
Charity workers believe people wanted to be generous by donating items but may not have realised they were out of date.
Helen Bull, from Cardiff Foodbank where the tins were handed in, said: “Probably what’s happened is that it is harvest time and lots of people clean out their cupboards and donate items that they have never used and don’t really look at them.
“Unfortunately what sometimes happens is that when an older person dies the family will clean out the cupboards and they want to donate and don’t necessarily realise that it was out of date.”
Cardiff Foodbank, which handed out 14,189 three-day emergency food supplies to people in crisis in 2016, tweeted about the find: “It’s a record!! Never had a donation to @CardiffFoodbank with 10d on before! @HeinzUK”
Heinz responded by saying: “Wow! That soup was discontinued over 35 years ago. Should be in a museum rather than a food bank! :)”
Ms Bull, who said it costs between £80,000-£100,000 to run the foodbank each year, added the charity had to waste a lot of food which was out of date.