do you know how banknotes look after being washed with the laundry?
genuine question, because I forgot a $20 with the laundry at work and I don't know if the laundry is going to look green or if I'm going to get a white $20 back and clean clothes...
Bills are made to be able to go through the wash for the exact reason that yours ended up in the wash, people carry them around in their pockets and it’s easy to miss or forget about. The bill might look slightly more worn but it won’t have all the color washed out or anything like that, assuming you didn’t dump it in a load of whites with a ton of bleach. It shouldn’t hurt your clothes either.
It functions that way as well, but durability for every day use is also a consideration in the material choice. Bills being uncounterfeitable isn’t particularly useful if they’re constantly being removed from circulation because someone left a bill in their jeans when they washed them.
The laundry will be light pink, the green color of the US bank note is actually an optical illusion deliberately put there as a counterfitting meassure, they use red dye but only the reverse side of the dye to make it appear green, it is similar to red/green color blindness.
Then when you launder the money, the dye gets jumbled and returns to it's red color, this is mostly noticable on the normal laundry since dollar bills.