Headphones
Think about it - most likely your headphones go from your ear to your coat pocket, to your purse, to the gym, to your purse and then back into your ears. Clean detachable rubber nubbins by soaking them in a vingear/water solution for 15 minutes; then let them sit for 10 minutes in water before drying.
For undetachable headphones, use a gentle mixture of soap and water on the plastic exterior and clean with a toothbrush to remove any lint from the grill.