Most of us would probably point to a bathroom or frequently used outside entrance if asked to name the dirtiest area of the house—but dirt lurks in some unexpected places. Here’s what to tackle during your next cleaning session. 1. Faucets If you’ve never removed the filter on the end of your faucet, you will find black, mildewy grunge that’s been filtering through the water you drink and use to brush your teeth with. Clean it: Every couple of months, remove the faucet aerator by twisting it counterclockwise, then soak it in vinegar for at least 15 minutes. (Take note of how it goes back together.) Gently brush all parts with a toothbrush to remove any remaining residue, rinse well, then screw it back on. 2. Handles and switches Think refrigerator door handles, light switches and, of course, the toilet flush handle. Handles are easily overlooked in cleaning because they’re …