Just in time for flu season, a new study carried out in six major U.S. cities found that the filthiest surface is at the gas pump.

Hygiene company Kimberly-Clark trained researchers to swab frequently touched surfaces in Atlanta, Chicago, Dallas, Los Angeles, Miami and Philadelphia.

The results revealed that the following surfaces contained the most germs: gas pump handles; mailbox handles; escalator rails; ATM buttons; parking meters and kiosks; crosswalk buttons; and vending machine buttons. In fact, nearly 75 percent of gas pump handles are highly contaminated with the kinds of germs that can make us sick.

According to health officials, most cold and flu viruses are spread when people touch contaminated surfaces. Doctors recommend frequent hand washing to reduce the risk of getting sick.