We all know paper money may not be the cleanest item we keep on us all the time, but we had no idea it could be this dirty.

Two bank tellers in Wenzhou, China have been infected with genital warts after gynecologists told them they caught the STD from touching dirty paper money. Most likely, according to doctors, the women were indirectly infected after handling the dirty money and using the bathroom without washing their hands prior.

One teller, a 30-year-old, claimed the only person she was sexually active with was her fiancé, who tested negative for any STDs. The other teller, who chose not to be identified, claims she has had no prior sexual experience.

According to doctors, most STDs, cannot usually be spread through mere contact with dirty toilet seats, shared utensils, public swimming pools or money. However, genital warts can be spread through skin-to-skin contact, even when no warts are visible. According to Planned Parenthood:

“Genital warts are spread by skin-to-skin contact — usually during vaginal, anal, or oral sex play. There is a chance genital warts can be spread even when no warts are visible. Treatment seems to lower the chance of passing the infection to a sex partner.”

Remember to always wash your hands after handling money, and it may also be smart to avoid cash transactions altogether if you are ever in Wenzhou, China.

Source: Shanghaiist Image via NYTimes