A clean car can give you a more professional look and a better feeling about your life… but can it also save you money?

Short answer: yes.

The long answer starts with the popular TV show, Mythbutsers. A viewer asked whether a dirty car might be more aerodynamic than a clean one. They figured that the dimples on a golf ball made the ball fly faster, so the texture provided by a layer of dirt on a car could do the same.

“Dimpled balls disrupt the air around them, creating a smaller wake behind them and reducing drag,” the mythbusters reasoned after doing some tests with golf balls.

Dirty cars? No. In fact, clean cars got an extra two miles per gallon compared with dirty cars. To be specific, the dirty car got 24 miles to the gallon. Washed, the test car got 26 miles to the gallon.

When the testers carefully encased a car with clay and created an evenly dimpled surface, they were able to get 29 miles to the gallon. That’s interesting, but not very practical for real life.

Clean your car for the environment

Depending on your mileage and the price of gas at your local pump, you might save real money by keeping your car clean. Even if you don’t, that extra two miles per gallon can definitely add up over time. If it takes 16 gallons to fill your fuel tank, you’re getting 32 more miles for every fill-up.

Do your part for the environment… or just enjoy knowing that one side benefit of a clean car is better gas mileage.