A stiff artist's brush or cheap metal handled "thow away" from a hardware isle/autos are great for getting deep into gears and crevices when cleaning.
On the cheapies, you should check for solvent reaction with the plastic bristles though. Like many things today, the production quality can really vary from order to order 
I'd avoid any solvent on the spark wheel until one of these "Tin Pro's" can comment on its abrasive adhesion quality.
