A composite mage showing a US $1 banknote covered with bacteria. The dollar bill was laid on agar gel for 5 minutes and then removed. Bacteria transferred from the banknote started to grow on the agar gel and after 4 days the colonies were photographed. Also photographed at the same setting on another agar gel was the banknote. Images of the bacterial colonies on the agar gel were transferred in Adobe Photoshop onto the image of the banknote. This combined image shows that banknotes harbor germs of microorganisms (bacteria) and that it is a good idea to wash one's hands after handling paper money.