OK, got me. What on earth is a metal straw cleaning brush?I agree. That’s what I’m going to do because coffee and spices are dry. One of those metal straw cleaning brushes will do nicely. Not sure why it needs to be dishwasher safe except for anal people.
I've used a damp cloth to rub around the bowl and tops of blades. Like casey I use a brush to get out the dust under the blades.
If you thinnk what you have ground is a bit oily and leaving either residue or smell - then give it a "rinse" by grinding some rice.
I don't use mine for coffee, only spices.
I have a different dedicated coffee grinder a friend brought me back from the Netherlands.