Removing Factory Undercoating from Plastic Items/Restoring Plastic

[moparcar]

I did some searching on how to remove undercoating from plastic and I find suggestions for heat guns, oven cleaner, mineral spirits, dry ice, and everything else. I'm working on restoring my inner fender plastic items and some of these have the really hard factory undercoat (at least I think its factory). Either way it is very hard. This piece I've cleaned since this picture with soap, water and simple green but it won't touch the undercoat. I don't want to scrape and dig into the plastic of course.

After you have these sorts of plastic items cleaned is there any type of product you put on them to make them new looking and not chalky? Something that perhaps "soaks" in a bit?

Thanks-Wes

[1 Wild R/T]

Do you have access to a good pressure washer? Put the spray tip down close to the edge of the undercoating, it comes off in chunks....

[Slotts]

Gasoline and a rag. It will not destroy the plastic and melt the undercoating.

Jim

[anlauto]

Gasoline and a rag. It will not destroy the plastic and melt the undercoating.

Jim

Either that or varsol.....I use a paint stripper from spray can.....

[moparcar]

Thanks guys! I don't have access to a pressure washer so gasoline or varsol it is! I appreciate the help as always.

Do you wipe them done with anything afterwards to make them fresh looking?

Wes

[Rich G.]

I just did the little plastic shields that bolt to the bottom of the frame rails up front. They had undercoating and overspray on them. I used lacquer thinner and a red scotch brite pad and then wiped them down with Mother's Back to Black and they look like new.

[RUNCHARGER]

Work them a bit to start with. You can break a lot of it up without getting too dirty. Then use thinner to clean them up afterwards.

[70/6chall]

I have used good old WD40 and a rag on the bottom of the plastic bumpers and paint on lower part of fenders on the newer cars. It seems to melt that damned tar from, road work, with some rubbing and doesn't bother the plastic or the paint.  Thanks,   Al

[Bullitt-]

I've had good results using mineral spirits to remove undercoating...
Brush it on , let it sit a few & wipe... may take 3-4, sometimes more, applications but it dissolves eventually... works on greasy stuff as well..

[AAR#2]

The large fender shields you show are plastic and the undercoat is usually pretty brittle after years of curing/outgassing. Simply flex the plastic a bit and it will begin to seperate. Pick off the large majority, then use a solvent as others have suggested.

[ZEN357]

Try some brake cleaner.

[Burdar]

The large fender shields you show are plastic and the undercoat is usually pretty brittle after years of curing/outgassing. Simply flex the plastic a bit and it will begin to seperate. Pick off the large majority, then use a solvent as others have suggested. 

This is exactly what I did.  Most of it came off in chunks by just flexing the plastic.  After a good power washing, the rest of it came off.

[Claudia]

  I used a media blaster (on low pressure) on most of my plastic stuff. 
It takes dirt, grease, undercoating and over spray right off.

[moparcar]

Thanks for all the suggestions! I appreciate it.

Wes

[shawge]

I soaked mine in hot water and oxy-clean. Whatever chunks were left came off after a few wipes with a wax/grease remover.