I have a '72 Convertible. While cleaning the black interior dash with amor-all I noticed a lot of black coming off on the rag. At first I thought it was dirt but I now think the plastic is breaking down.

HAs anyone experienced this? Is there a better product to clean and shine the interior plastic?

 

Is it possible your dash was originally a different color and was repainted black, and it is the paint color that is coming off?

 

No, it is black originally. It is almost like the Amor-all wipes are deteriorating the plastic.

 

It's more likely that the plastic has deteriorated already and the armor-all wipes are just picking up the "dead" plastic .
Armor-all will help to slow deterioration.

 

I would clean the dash really well, in my cars I use a 1:10 dilution of Simple green in a spray bottle and a nylon brush like you might use to clean the kitchen or bathroom, then wipe down with a microfiber. Then I spray with water and wipe down again with a clean cloth.
Once it is dry I spray on 303 aerospace protectant and wipe/buff.

I would first only clean a very small inconspicuous area to check in case too much color comes off or something, but I think you might be OK.
303 aerospace is great stuff and will serve you better than armor all; granted, while people like to hate on armor all, they have been improving their product.

 

Don't use armorall.

The best dash treatment is vinyl-x