It is not really necessary but I do it just to keep my area clean. I have an air compressor and just use that to blow off the excess dust outside. Don’t get crazy with it, don’t jam the nozzle in the bushings or or anything like that. Just a light sweep with the nozzle removes the dust plenty easy. If I didn’t have a compressor I’d use a dry paintbrush or just find a container to store the mill in.
If anyone has brewed in a commercial brewery, what do they do? My experience in ones with dry mills like we have is - not much. Clean out the auger and area of dust, that is about it.
In the ones I have guest brewed at it is to keep the mess down, less food for vermin, the auger is drained and used in the next batch if close enough, or discarded if the color/malt is too far off. Dust on the floor is discarded in the trash. Just saying that once milling is done, and auger in the basement may have about a half bag of malt in it that will not feed up once there is not more malt to push it up. That is money.
I have had my MM-3 mill get clogged up and the free roller not want to turn. I’ve had to take it apart and clean it out around the bushing. It had a lot of dust build up between the end plate and the roller. It had probably ran 10-15 sacks through it. I would think blowing it out with an air compressor now and then wouldn’t be a bad idea. Maybe some food grade lubricant too.
Speaking of critters, I used to cover my hopper and mill with an inverted paper bag, but this just invited roaches to live in the nice darkness. Now I keep it open.
I use my shop vac to clean up the bottom of the board it’s mounted on. Since I’m already there and the vac is running I do a quick pass through the hopper to get any big stuff.
If the static didn’t cause a bunch of chaff and dust to stick to the board above the bucket I wouldn’t even do that much. Humidity in Iowa (and many other places) can go from 15% to 95% in a few hours several months of the year. I don’t want to have dust clumping everywhere in the shop so I vacuum, a lot.