I have a Mazzer grinder (super jolly) and recently replaced the burrs. Noticing the burrs had a lot of what looked to be coffee sediment, I dunked them into cafiza to try and clean them... Once I pulled them out, there were a serious of dark spots (obviously from where teh cafiza clumped). Is there any way to remove this dark stain from the burrs? Does it matter?
Was this bad to do?
The burrs are steel, so the dark spot are oxidation on the surface. Not really a big deal. Just grind a bit of coffee through them before you put it into use again. In the future, soaking in solution is likely do nothing other than oxidize the working edges of the burrs, effectively dulling them. If you really want to clean them, just use a stiff toothbrush or grindz tablets (although for me the jury is still out on the effectiveness of grindz).
I sometimes find used mazzers locally online and take them apart to refurbish them. I always start by removing the attachments off a shop vac hose, remove hopper, and place the hose over the still installed burr set (where the beans enter). I seal it with my hands and let it vacuum for 10 second. Almost always this approach removes a majority or all of the caked on coffee residue, and is easy to do daily with a working grinder on the bar using a small vacuum at closing. If you have an electronic model, simply remove the hopper lid, start a grind cycle and place the hose under the dosing funnel, use your hands to make a seal. Clean as a whistle. We have a hose that is designated only for grinder/counter cleaning and contact so it isn't dirty.
Thanks for the awesome response, exactly the answer I was looking for. And I love the idea of a vacuum!
Running white rice (uncooked) through your grinder is another "old school" trick. It is supposed to remove the oils that build up and get rancid. Probably want to adjust the grind coarser first.