I use a steel "toothbrush". They usually come in a set of three; one steel, one brass, one nylon. You can find them at Harbor Freight pretty cheap.
CBJ # 22569
Member of the 100+ Contest Club
Judge Number 6
competition BBQ team
Possibly the only judge ever to get an award from a bunch of cooks
UDS 075 UCB WSM and a bunch of other stuff.