How do you clean a hobbed bolt or pulley? I do have some problems with material feed and I think I should do something like this.
I use a tooth brush at times.
A hobbed bolt should at no time have little plastic shreds in it - if it clogs itself up, your idler tension is either set too high or too low.
I use random pointy objects for cleaning out the hobbed bolt if it ever does get clogged. With a normal M5 or M6 hob, it practically cleans itself of small shavings as long as the hobbed part is mostly clean.
X-acto blade, just run it side to side to clean out each trough.
.22 or .17 ga rifle bore cleaning brush, chucked in a handheld drill.
I used paint brush cleaner tool set. Its a set of hard brushes, one even has brass in it. I was a one minute job.
Needle
OK, I’ve got the hobbed pulley cleaned with a needle und a tooth brush. The first print afterwards was just perfect. 
The second not: The pulley got clogged again ( I suppose). So I have to change the idler tension.
I use compressed air
@Matt_Kraemer1 it can also mean that it is too tight - when it is, either the pressure starts deforming the plastic and it gets stuck further down the extruder or the hobbed bolt is directly shaving the filament as its teeth dig in and rotate out.