for tire and misc fine cleaning, use disposable alcohol wipes...not those "wet-nap" peices of junk, but those disposable "lens-cleaning" cloths that use nothing but alcohol in them. Beware though, isopropyl alcohol is a very effective de-greasing agent.
It sure does make your axles shine though
Toothpicks make for great quick cleaners for your gears...just gently slide out any large peices of matter frm the gears. It's great for those times you know a deep cleaning will be pointless since it will get dirty again in 2 mins anyways.
Oh and the bit char-g run-in trick works as well, since all it really does is wear down the gears to the point of running smoothly. Also cuts back the noise level of the car by a reasonable amount.