Loc Challenge: Trapped build-up and lint

If you haven't seen any posts from me about loc challenges that's because for awhile, I didn't have any. It seems like the more my locs mature, the less issues I have. I've gotten over and pruned the frizziness. The scalp is chronically dry but I kinda just deal with it. And the locs grow without any issues.

BUT---I have come across a problem that had me in the mirror for hours.

Trapped build-up and lint. 

This is bad. This is very bad...