Espresso at home was getting some weird, off flavors. Running Grindz through my ceramic burr grinder fixed everything.
Grindz are pellets of wheat and rice flour that clean off the contact surfaces in your coffee grinder. After running the cleaner through, grind a few measures of coffee to clear out the Grindz and you are done. It was magic.
You should also clean out the bowl that holds your beans, and the chute that delivers the grinds. I used warm soapy water and then wiped them down.