"The ten pence coin was originally minted from cupro-nickel (75% Cu, 25% Ni), but since 2012 it has been minted in nickel-plated steel due to the increasing price of metal"
I knew that, Mikey: I just wanted to use the word "ferrous". Anyway, we've had plastic 5, 10, 20, 50, and 100 dollar bills for quite a while now. Be careful: they tend to stick together so it's easy to mistakenly give out two bills instead of one!
Dammit, why didnt they do that when I was a youngster, I used to spend hours trying to get money out the local wishing well, it would have been so easy with a magnet on a string!!