Only if it's designed to be cleaned (like a K&N oiled cotton filter). Standard paper filters cannot be effectively cleaned — tapping or blowing with compressed air damages the filter media. At $10-$20 for a new one, replacing is safer than risking engine damage from poor filtration.

Replacing a clogged filter restores lost performance — better throttle response and 1-3% fuel economy improvement. But replacing a clean filter with a new one won't add horsepower. The real benefit is maintaining existing performance.

Some older vehicles (pre-2000) and base-model trucks don't have cabin air filters. Check your owner's manual. If your vehicle has the housing but no filter installed, buy one and install it — you've been breathing unfiltered road dust.