A clean air filter may just be the little known trick to good fuel economy. That’s right: a dirty air filter restricts the flow of air into the engine, which harms performance and economy. We think that solvable problems are the best kind to have, so we’re happy to report that changing an air filter is actually pretty simple. Remove the filter and hold it up to the light. If you can’t see light coming through it, it’s time to replace the filter. Better yet, replace that old disposable filter with a reusable one (found at an auto supply store). A permanent filter is much less restrictive than its disposable cousin and cuts down on waste. Keep your car (and us!) breathing easier by checking the filter regularly, and impress your friends with your DIY skills at the same time. Now, aren’t you sexy?