After riding, let your gloves breathe and dry out. Do not store them in a closed container, jacket pocket, helmet or tankbag.
Also, Held recommends that you wash your gloves.
When you ride, all of the sweat, along with the oils, acids and salts contained in your sweat, will soak into the leather. After a while this built-up sweat contamination may cause the leather to fail prematurely. You should wash your gloves with soap and water to remove this sweat build-up.
Rinse the gloves with clean water, do not use high pressure. You may also let the gloves soak for awhile in clear water to loosen up and draw the sweat out of the gloves. Now wash the inside of the gloves with soap and water. Dilute soap in the water; do not apply soap concentrate directly into gloves. Regular antibacterial liquid hand soap works well. Allow the gloves to soak in the soapy water. Using your hands, work the inside surfaces of the gloves. Rinse and repeat as needed until you are satisfied that the gloves are clean. Rinse the gloves thoroughly. Do not twist or wring the gloves when wet; this may distort the shape and fit of the gloves. Use your fingers and hands, starting at the finger tips and working down, press or squeeze the water out of the gloves. You may place a small folded towel in the gloves and press the water out of the padding and Kevlar lining in the back of the gloves. Now allow the gloves to dry slowly. Do not place in direct sunlight or expose to high heat. Lying in front of a fan in the garage is a good place. Just before the gloves are completely dry, put the gloves on and shape them to your hand while damp. Remove the gloves, trying to keep this hand shape in the gloves. Allow to continue drying. After the gloves are completely dry, apply a good quality leather conditioner. This is very important. Properly treated and conditioned (oiled) leather will breathe and the internal micro fibers will move freely in the leather. Use a good quality leather conditioner that will allow the leather to breathe. Apply conditioner generously and rub into the leather. Allow the conditioner to soak into the gloves and reapply (you can do this in the sun). Wipe off any excess conditioner and make sure the gloves are not slick on the motorcycle controls.
You should do this at least once a year. More often if you sweat heavily, ride in a hot climate, notice salt rings (white stains) or discoloration from repeatedly being soaked with sweat, if the leather gets hard or stiff, or if you begin to notice a smell from the gloves.