So recently after a good amount of miles after i removed my cat, i noticed on my rear bumper the passenger side was geting yellow/ brown. (single sided exhaust) Due to hydrocarbons? carbon build up? please correct me. Now the question is what is a effective way to clean it up? i wash my car very good but the car soap just dont do the job.

 

you could try a clay bar. if it were me, id use just a small peice of the clay instead of the whole bar. you could always use another smalle peice if you needed too, but you wouldnt ruin the whol thing. good luck!
james

 

stains on the rear of a white car are from the exhaust and road debris...
as shotgunjimmy suggests the first step is wash and clay. that will get any imbedded problems. next would be a polish to get any stains that the clay doesnt get.

if you need details on these processes, check our how to threads and then post questions back here-

the best suggestion, without any doubt in my mind, is to post up in your local forum on this board that you need help with clay and polish and that you will supply refreshments... you will make a new friend, get your car looking new and will learn how to do it all for the cost of refreshments and maybe some supplies. win/win if ever i knew what that meant- and by far my most popular suggestion. more thanks for that one than anything else that i suggest.

 

i just used bug and tar remover from autozone.... it wiped right off!! lol thanks for the suggestions anyways

 

I have not taken of the Cat however I have noticed a few yellow spots near the front part of the rocker panels that I was able to remove with the following:

A few quick sprays of Carb clear immediately followed by water and soap and clay bar.

I know the cleaner is not recommended for the paint but doing it real quickly worked for me.

After that I used Meguiars wax and have waxed it regularly so it does not come back.