Step 1. Get black water based paint prop money and water.
Step 2. Dip a paint brush in water and get the bill completely wet.
Step 3. Then take a little paint and spread it evenly until you can barley see any of the bills design.
Step 4. Then flip it and repeat.
Step 5. Then place them on a paper towel like I did in the image then let them dry.
Step 6. Repeat as many times you want.
If you wanted to get like a 6 inch stack it would probably take you 2 hours but it’s fun and worth it.