Slight damage - how to clean?

Step up the cleaning process until it comes off.

1 soap and water
2. Wax and polish
3. Clay bar
4. Rubbing compound
5. Possibly using a Buffing machine (without rubbing compound on the surface)

If rubbing compound won't remove it, it's probably going to need a body shop

 

Wax and polish does the least amount of damage, rubbing compound will start stripping the clearcoat. I don't like using rubbing compound unless it's totally necessary

 

Yeah, an old terrycloth towel rag with a dollop of of car polish. May get it all, should at least diminish it.

 

I've had success with one of those scouring pads one uses for nonstick pans...they're also good for getting bugs off the front bumper and side view mirrors.

 

I'd be cautious with those, try on a hidden spot first. May take the gloss off, quite quickly.

The worst mess was when I parked under a tree weeping sap. I used a kerosene wetted rag with a dab of car polish (non abrasive car polish, not cleaner wax) and took it one spot at a time.

 

A light spritz of WD-40 on a rag might do the trick, followed by gentle rubbing. Put some car wax on afterwards.

 

Rubbing compound is my go-to. May not get it back to perfect but usually gets it looking good enough that no-one else will know!

 

The magic eraser is somewhat abrasive too. Again you could try, but start with a hidden spot.

 

Years ago with a previous car that was in perfect cosmetic shape when I got it, someone backed into it and left a perfect imprint of a hitch receiver in my back bumper. As in your case, no note. After fuming a bit, I told myself, "Oh well. It was gonna happen eventually. Now I don't have to wonder when."

 

I've used it before to remove some adhesive residue from when they take off the white plastic from newly delivered cars. Should work on the OP's black streaks as well. Worth a shot...

 

I wonder what's the main ingredient in WD40, might be kerosene?

Yeah WD40's a good low volatility cleaner; I'll sometimes use it for hand cleaner, before the orange Gojo stuff.

 

Try using a lite application of headlight cleaning compound. It’s formula is about the same as 3M’s finishing polish, called “Finesse”.

 

I've got a couple of powders from my furniture refinishing episodes: pumice (quite aggressive, will take gloss off, leave it mat) and rottenstone (slick as snot, will bring it back to gloss). Just a thought, lol.

 

I would re-wax the cleaned area.
Glass cleaner can have ammonia in it and might be pretty tough on wax.

But at least it worked.

Basically, my advice in the future is to use and try automotive choices 1st. Forays into kitchen and bathroom cleaners and tools, are really unnecessary and potentially damaging.

If your wife had used the wrong cleaner, or you had used a too abrasive pad? You could be talking about how minimal cosmetic, perfectly removable damage had become something much worse.
Stick to the automotive aisle. Lots of good products designed to clean your vehicle. IMO no need to experiment with the same tools used to clean toilets or smudged bathroom mirrors.