simple green & purple power are our local (WessMass) solutions. Spray'n scrape anything U can 1st! Plop into a bucket. I believe covering 1 or 2 components /or/cautious direction of spray to B enuff for 'safety' @ the 2nd stage @ car wash.
The car wash has special equp (by local law) to take whatever we dish out. Each city/state requires something else (seperators, containment, etc).
I too would feel a lill weird leavin a big mess for next customer/wash owner,personnel so throw in a few more coins w/truck out & spray the gunk 'down the drain' right there. Spray frm the direction of ur vehicle so as not to get it on.