I use an old car detailers trick. Take a cheap ( and when I sat cheap I mean inexpensive) 1" paint brush
and cut the bristles at a 45 degree angle. Works really good.
Give a little tug on the bristles when looking at brushes. Some of the the bristles will pull out from the ferrule
on the poorly made brushes.

The Acid brush from the plumbing section is the way to go. $1 and you get a pack of 5. Good little addition to my supplies.

I use a plastic handled long bristle brush, the brush will bend to get around tight spots and the long bristles get clear back into the burrs. Just remember to give the burrs time to stop when the hopper is empty before you stick that brush in there to clean. Some of the big grinders take quite a while to spin down when there are no beans in the hopper. My brush has a short bristle side and long bristle side.

Am I the only guy on here that owns a coffee brush? The acid brush is a nice idea but after using them for decades to apply flux & grease in my shop I don't know if I could use one around my coffee. Too many crusty acid brush memories I guess. Anyways here's a pic of my cleaning tools minus the wife's Meile vac. The short one came as part of my free cleaning kit when I bought the machine & I found the long one at Linens & Things. As you can see by the jagged ends its gotten a little too close to spinning burrs a few times but otherwise is holding up well. The chopstick is my favorite for knocking grounds out of the chute. Adds a nice "woody" flavor to the shot if the burrs haven't quite stopped spinning.

speedstar wrote:The Acid brush from the plumbing section is the way to go. $1 and you get a pack of 5. Good little addition to my supplies.

And with a pliers you can bend it 45° and re-crimp the bristles to get into the groups on smaller machines! I trim the length a bit to make them stiffer.
-Richard