I have a $50 banknote (a $50-dollar bill) in my pocket. I go to a restaurant and pay for dinner with it. The restaurant owner then uses the bill to pay for the laundry. The laundry owner then uses the bill to pay the barber. The barber will then use the bill for shopping. After an unlimited number of payments, it will still remain a $50-dollar bill, which has fulfilled its purpose to everyone who used it for payment and the bank has jumped dry from every cash payment transaction made