i do this after i use them (been doing this for years) but it wouldn't hurt to do it before. put the hose inside the mitt and hold the cuff tight and let the water flood the inside/out and massage the outside of the mitt to release any debris/contaminants while the water is flowing (you can also spray the outside of the mitt as well). you can also get a clean bucket of water and thoroughly clean it by massaging the mitt inside, so you can see anything you may have missed though i don't feel it's really needed after doing the formentioned...