Raggtop protectant is a paraffin wax based product that is made specifically for the NB and other german fabric tops.
I would strongly recommend that you not use a caustic spray or steel wool of any kind on the glass.
You risk getting caustic overspray on painted surfaces and will surely risk scratching either the glass or painted areas near the glass with steel wool. It does'nt matter if its fine or not, steel wool will scratch and you might get tiny pieces to fall around and into the window glass runs or seals and that stuff will rust.
So, the easiest way to remove overspray if it has dried on the glass is to use a razor window scraper and carefully scrape the heaviest quantity off and then use a quality window cleaner to clean any remaining residue from the glass.
And, I do the same thing Duffy does when I spray my roof. Cover as much as you can and minimize the overspray cleanup.
Good Luck
