Fill up a small pale with warm water, add a small amount of CLR (read the directions!), insert the part that needs to be cleaned (sink knob, shower head, faucet screen, etc.) for a couple of minutes (read the directions!), remove the part from the solution, rinse. I wash my shower head with a little clear soap afterwards too and rinse repeatedly so that I'm 100% sure I'm not bathing in CLR the next morning.