Re: black plastic effin up my shizz up
use a mildly abbrasive conditioner (miguires offers 2 or 3 different types) then a polish, then a wax.
waxes are used to simply seal the clear coat from external eliments (tar, acid rain, dirt, whatever) so you are actually SEALING that black stuff under the wax next to your paint... kinda like putting some strange man in bed with your old lady and then putting a blanket over them. it masks the problem, may reduce the appearance a little, but the problem is still there...
use the abrassive compound to remove the wax you've put on it and to litterally "scrape" the contaminats off the paint. On show cars with 3/4/5/9/10/++ coats of clear coat they occationally wet sand the clear coat to pull the swirl marks out. The abrassive compound is doing the same thing, but on a softer and gentler level...
after this you have to use a polish (obviously you dont "have" to do anything, but its what i am suggesting.) the polish will fill the minor (think on the molecular level) gashes/tarnishes that the abrassive compound makes (and damage that occurs naturally.)
Finally use a wax after buffing off the polish. this will seal teh paint and polish from external eliments.
honestly, thats all i can suggest. if it doesnt work, i have no idea how to get it out. 3M makes a buffing compound body shops use to pull out orange peel, swirl marks, keying, and other things. that would be my final suggestion. its basically a heavy abrassive compound (like i already suggested) but its MEAN... lol. its not as bad as wet sanding, but its not as gentle as miguires or mothers abrassive buffing compounds.