Why U.S. bills behave differently from ordinary paper
A dollar bill is called “paper money,” but its base is a woven blend of cotton and linen fibers, not the wood-pulp material used for most writing paper. Those long textile fibers are interlaced into a tough sheet. Cotton gives the material a flexible feel, while linen fibers help reinforce it, so the bill can bend and fold repeatedly without splitting as readily as ordinary paper.
That construction matters because cash is handled constantly: it is folded into wallets, passed between people, and rubbed against other bills and surfaces. A pulp-paper note would tend to weaken and tear much sooner under that repeated stress.
What happens in the wash
Water alone does not make the fiber blend dissolve or turn to mush. A bill may come out of a washing machine still in one piece, but that does not make it waterproof or laundry-proof. Tumbling, heat, detergent, and contact with other clothes can abrade it, leave it crumpled or stained, or damage its printed features. The fabric-like structure improves its odds of surviving an accident; it does not guarantee an undamaged bill.
Durability has an economic payoff
A note that tolerates frequent handling can stay in circulation longer before wear makes it unsuitable for use. That reduces how often a replacement has to be produced, though worn or damaged bills still need to be taken out of circulation. The blend is a practical compromise: familiar enough to print and handle like paper, but sturdy enough to withstand the rough routine of cash.
