Russell Bateman December 2019 last update:
How to Repair a Scuffed Bumper
Notes for the repair video above:
This cute trick is supposed to work (I've seen it in a YouTube video) to remove a dent in an aluminum panel. They guy doing it didn't say much useful as he did it. I read a comment whose author asserted that dents made by hail come right out although he said that he used the hot sun and some dry ice.
The oily film is from out-gassing of plastics in the car, especially in hot summer, also from Armor All™—or smoking, leaky heater coil, etc.
To clean rear, tinted glass, you don't need to use anything other than the microfiber towel and a little cleaner like Windex™ because, while the problems of a windshield are completely noticeable, on tinted glass you see little or nothing.
Start by cleaning the outside glass very well so you can see, while working on the inside, nothing on the outside.
Steps...
Tips...
Resources: