wideglide

have 73 442 ive owned since 1978 im getting back on the road.trying to make interior presentalbe for now,the GM plastic,grainy trim and dash.if i remember right,had alot of armorall on it when i bought it.. been trying to clean it up abit,using TUFF STUFF,meguirs, and griots ,even using a toohbrush trying to clean the grain,looks great wet,then dries chalky! any thoughts,thanks

RAMBOW

Most likely you are going to need to prep and paint it. Once plastic starts turning chalky- it means UV has damaged the pigments in the plastic itself.
GM's black plastic is still pretty durable even when it starts getting that chalky look- but the Colored plastic parts, once they start degrading, the plastic itself disintegrates.

What color is the plastic?

If its black you have a couple different options, if its a color, proper prep & repainting with SEM color coat or similar product designed for plastic is your best bet.
If its black, SEM Color Coat Landeau black is a dead ringer for the original black... But I have also heard of people using liquid shoe polish on GM black plastics with good success- which might be cheaper and easier than the multi step, multi-product cleaning & prep process required for the SEM stuff.

anyway, a few leads for you! Hope this helps.

Olds64

^^^ THIS ^^^

You can use a mild soapy water solution to clean the dash before you paint it. Follow up with degreaser (or isopropyl alcohol) and a tack cloth. Make sure you use adhesion promoter or primer per the manufacturer's instructions.

gs72

This stuff works great.

303 Marine Aerospace Protectant - Provides Superior UV Protection, Repels Dust, Dirt, & Staining - Dries To A Matte Finish - Restores A Like-New Appearance, 32oz (30306) Packaging May Vary - Walmart.com

gs72

We used this on my vinyl top and it made it look like new. The plastic fender flares on my wife's jeep were faded and chalky looking. It made them look like new also. I would give it a try before you buy paint. I think they make a 16 oz bottle also.