Long story short: I was polishing my rear plastic window and didn't take proper precautions. I got the "white polish stuff" on the soft top by the plastic window. There is bunch of white marks. It won't come off after much cleaning.

any advice, comments, or suggestions

 

you didnt really tell us what you have tried so far...
or what the white product was-

so my best guesses:
i would first try car shampoo or a top cleaner (raggtopp is a good one) with a top brush (similar to a tire brush- moderately stiff). scrub the area well- after allowing the cleaner to soak the area for a few minutes.

be sure to use a good top protectant after drying (303 or vinylex are a couple of good product choices)

 

I washed my car and tried to scrub it with soap, but it won't come off. It is some kind of plastic polish chemical.

help

 

then i would go back to my suggestion above-
you can skip the car shampoo part, but try the rest.
especially raggtopp cleaner with a good brush after soaking the raggtopp a few minutes.

 

Where do you get raggtopp cleaner? I looked at pep boys, but they didn't have it.