Flu vaccines this winter are only 23% effective, and elderly Americans are being hospitalized in record numbers, according to the CDC. To prevent the spread of flu and other illnesses, wash your hands after touching these six surfaces at home.

1. Money

It’s cringe-inducing to wonder who last handled your cash or coins. A sick drugstore customer buying medicine? A child sticking the quarter in his mouth? A person traveling straight from the bathroom stall to the vending machine without stopping at the sink? New York University researchers found in 2014 that a dollar bill carries about 3,000 different types of bacteria, so wash your hands after shopping.

2. Towels

Washing your hands is a great step in preventing illness, but where you dry them must be clean, too. University of Arizona researchers found in 2014 that 89% of kitchen towels contained coliform bacteria, and 25% contained E. coli, which gets introduced to kitchens by uncooked meat. After each use, machine wash towels using warm water for colored towels and hot water for white ones.

3. Door Knobs/Door Handles

Doors get us from point A to point B, and they open our microwaves, ovens and refrigerators. But in 2014, University of Arizona researchers found that one germ-infested doorknob could spread a virus to 40-60% of a workplace staff within two to four hours. Microbiology professor Charles Gerba said people can stop the spread anywhere with a simple item: Disinfecting wipes. In the studies, the wipes alone reduced occurrences of the virus by 80%.

4. Electronic Devices

Phones, tablets, TV remotes and gaming controllers all spend hours in our hands, and they’re germy. We pass around TV remotes and video game controllers while stuffing our mouths with food. And our cell phones, which follow us everywhere, contain 18 times more than the amount of germs you'll find on a toilet handle. Debate continues on how to clean a phone or tablet without harming the screen, but the New York Times offers ideas you may try at your own risk.

5. Light Switches

We finish touching our light switches after a quick flick, but nonetheless, they're communal locations that everyone lays hands upon. Studies show light switches can have as many germs as a trash can. Run a disinfecting wipe across the light switch to eliminate the germs living there.

6. Washing Machines

We'll save you the stomach-turning specifics, but just know that underwear introduces bacteria to the washing machine. And when wet laundry sits in there after the cycle, the bacteria invades, according to ABC News. Use hot water (140-150°F) or bleach to wash your clothing when possible. When it's not laundry day, run a wash cycle with bleach and no clothing to rinse your washer. Always wash your hands after handling laundry.

Want tips on how to fend off the flu virus your hands may have come into contact with? Check out CleanFreak.com's employee hygiene and handwashing guide.