Normal
I just get all the big dirt chunks off with the pressure washer and that gets alot of it and then after that i usually get a cloth and wipe down the parts that the washer couldnt get off (ud be supprised of how much u can get off by even scrubbing lightly). and then what alot of guys use is wd-40 because sence its kindove a lubricant the dirt slides or comes off the plastic alot easier and it will keep ur fenders looking good. and another thing is if you realy want to make it unbelivably clean. use cleaner like justincr250 said and then put tire shine on JUST the plastics and it puts an unbileavble shine to it. but the tire shine collects dust fast so after a few laps it will normally look dirtier than most bikes.