I didn't realize carb cleaner was so damaging to plastic and unfortunately left marks on my car's plastic grill. Notice how the matte-ish black plastic looks shiny like water was spilled on it, but it is actually just "burns" from the carb cleaner.
Any ideas how I can repair this or at least make it look better?
Remove the grill, thoroughly clean it then spray it with plastic paint or even replace it. The damage caused by the solvent is most likely permanent.
As you found out, the warnings on carburetor cleaner to avoid contact with plastic and paint are for a reason.
The black plastic looks faded, not necessarily an intended matte finish. Before spending a lot of money to have it painted or replace it, try washing it with warm soapy water and completely dry it. Then use a plastic restorer (like the wipe on kind found at auto parts store) to restore the plastic surface.
(This picture is just for reference)
Here is a helpful video on how to restore and fix faded plastic trim on your car.
You cannot remove the marks that it has created but yes you can hide them by using after market products like dashboard polish since dashboard is also plastic or a insta-shine sponge.All you have to do is rub that sponge on the plastic surface that will give you a uniform texture
I sanded out the damage for the most part. Some of it was surprisingly deep, but using fairly fine sandpaper (grits: 400 -> 600 -> 1000 -> 2000) seemed to work well.
I will try some plastic restorer if I'm still unsatisfied.
After you use the super fine grit sandpaper or steel wool, try this: http://www.retr0bright.com/make.html
I know it sounds like it won't work, but it would lighten the darker spots to be more like the faded black part.
Try small sections first.
