i use simple green and a detailing brush (basically a tooth brush) to get in the cracks, and since i hate dirt in my chassis screws i take a pocket knife and scrape the dirt out once a week, which is normally how often i run at the track.
simple green on tires works great too, brought some panther clay compounds back to life i had in my garage for a year. if i want really sticky tires for the day ill use a bit of extra on the tires and clean them 1-2 hours before i go to the track, softens up the rubber, and as far as i can tell with stock truck it doesnt accelerate tire wear!
