Unlike Gremlins, money can't be ruined by water. Cleverly, it's made of cotton fibres and it won't absorb water like cellulose paper (the stuff from trees). This means when you've left £20 quid in your back pocket, it will still be in tact even after a couple of spins.
However, this rule doesn't apply to money that has been buried for 13 years, as Ma Lin, 63, a builder from Yuanyang, China discovered.
Ma buried 80,000 RMB (£8,000) worth of banknotes under his bed and kept them in a jar but the container cracked in a frost, allowing water to get in. When he finally dug up his stash it was rotten.
Even worse, the 1990s notes are now so rare in China that collectors would pay nearly double their face value if they were in perfect condition. Ma is seeking help from currency experts to see if any of the notes can be salvaged (someone help him, please).
"No bank will touch them as they are. My wife is very unhappy with me," he said.
He's probably a little unhappy with himself too.