Have some cash that you want to double? Try a little bit mandrake!
Place a mandrake root in the light of of a full moon. Around the mandrake root, place the money you wish you double. Leave it there overnight.
The next morning bury the root and spend the money. Within 30 days (until the next full moon) you should see your initial money doubled.
This works better with silver coins than with dollar bills. But it still works.