Boxing gloves encounter a lot of action during their lifetime; getting covered quite literally with blood, sweat and occasional tears. If you don't keep your gloves clean, they'll develop a strong unpleasant odor. Even worse, your gloves can house bacteria that can lead to infections endangering you and your opponents.
Wipe your gloves inside and out with a paper towel when you're done using them each time. This will minimize the moisture that bacteria love so much.
Unlace or unwrap your gloves and open the wrist as fully as possible, folding the wrist straps over themselves. This will maximize the air flow between sessions to help air out your gloves.
Spray your gloves inside and out with an odor-eliminating household product once per week.
Store your gloves in the open, not in a gym bag, between sessions. Nothing breeds bacteria like a moist, dark, warm environment such as your gym bag.
Wipe down and open your gloves like you do after every workout.
Pour a mixture of one part vinegar to two parts water into your spray bottle. Shake to mix thoroughly.
Spray the outside of your gloves with your mixture and wipe dry with the paper towel.
Spray the inside of your gloves with your mixture. Pat dry and allow airing out to dry the rest of the way.
Store your gloves with the open wrist holes pointing toward a light source. Light kills much of the bacteria that vinegar won't.