The Washing Machine
More of this: Loading up the interior with a cleaning agent.
Less of that: Replacing a moldy rubber gasket.
Residue from detergent and liquid fabric softener can build up over time and cause a funky smell. Once a month, run a load with just hot water and an oxygenated-bleach cleaning pouch (Tide Washing Machine Cleaner, $6.50 for three, soap.com). Then use a nonbleach disinfecting wipe for hidden mildew-prone spots, like the rubber gasket. As a practice, air-dry the washer after each use by leaving the door open.