[alexander_busek]

They did something similar during WW2 when copper was needed for the war industry; they made these red cardboard type pennies. MY grandad had a cup full of them as souvenirs.

Nope.

During 1943, one-cent pieces were made of zinc-coated steel. These coins were also known as "1943 steel cents."

In the years leading up to 1943, they were made of bronze (95% copper, 5% tin and zinc). From 1943 till 1946, they were made of so-called gilding metal (95% copper, 5% zinc). From 1947 till 1962, they were again made of bronze.

WIKIPEDIA:

In 1943, at the peak of World War II, zinc-coated steel cents were made for a short time because of war demands for copper. A few copper cents from 1943 were produced from 1942 planchets remaining in the bins. Similarly, some 1944 steel cents have been confirmed. From 1944 to 1946, salvaged ammunition shells made their way into the minting process, and it was not uncommon to see coins featuring streaks of brass or having a considerably darker finish than other issues.

No federal mint made cardboard one-cent pieces.

Regards,

[ABN 505]

My kid metal detects around our property often, he came across a 1812 Large Penny next to a stone wall a few years ago. It was tarnished but mint, all the newer penny's he finds are rotting and disintegrating from the acidic soil. People in the future will never find coins from this era as they rot in the ground unlike older coins.

[SkyDancer]

In further study, they were OPA tokens: https://bobstokens.com/the-history-of-opa-tokens/