Hmm. I just rinse the cup while the water is filling the tub. DH hated the cup said it made a mess. One day he saw me getting ready to do a load and said Oh that's how you do it. I had hot water running at the time. Just hold the cup at an angle to where the hot water doesn't touch your fingers. Too simple. I use ALL Free 'N' clear. Has the small pushbutton plunger, not pump. When you're done with the cup and after rinsing the cup just put it back on no messes.