pre carpet cleanup

[low13]

been messing around with my b4 at a bmx track near me and have this clay based sandy crap all over my car at first i just thought it may wipe off but after a considerable amount of cotton buds and mums cleaning stuff i still can't get into the knools and crannys anyone have a good way to efficeintly clean your car without compressed air as the clubs just started racing again and i know there pretty fussy about dirt etc.

i know i shoulda put this in general but i am an arse.