[eqvinox]

Toothpicks work great for this if you narrow them a bit with a knife.

As a woodworker I'm surprised you didn't have that idea :D

(Like, c'mon, toothpicks aren't immutable objects that fall out of question just because they're a bit too large)

[fingerlocks]

huh, when I make em thin it's too flimsy to get the packed sawdust out. Maybe I need to get some premium hickory toothpicks

[eqvinox]

Hmm, no idea if we have different toothpicks around here...

What also works (and funnily enough is also called a "toothpick") is the flat plastic thing some "swiss" pocket knives/tools (Victorinox brand) have.