From E-how :
Fill the sink with warm (not too hot) water.
Add four to six drops of the liquid dish soap into the water.
Place the workout gloves into the soapy water.
Squeeze the water throughout every finger of your workout gloves. Use your hands to scrub the outside of the gloves while the gloves are under water.
Remove the gloves from water. Turn them inside out.
Soak the gloves back into the water. Repeat step 4 in order to clean the insides of the gloves.
Remove the workout gloves from the water once more. Hang the gloves indoors or outdoors so they can air dry.