First use a razor blade to get off what you can. Then try Goo Gone.

I should add that if a razor is not strong enough, get one of those paint scrapers from Walmart or Home Depot. This is what I would use. You can probably get it way cheaper at Walmart rather than Amazon but this shows you what I mean: https://www.amazon.com/Bates-Paint-Scraper-Painters-Wallpaper/dp/B071XDP685/ref=sr_1_1_sspa?dchild=1&keywords=paint+scraper&qid=1598999294&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyUFhEWk5CWDdHTFNTJmVuY3J5cHRlZElkPUEwNzQzNjM2MUdGOTdBV1E5NlkyTiZlbmNyeXB0ZWRBZElkPUEwNzM5NjIwOUhBVlBLM0NTQU03JndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

@jca2 That’s an idea, though I’m worried if I might scratch the window itself. But it seems to be so stuck that the only way might be to physically remove it like you suggested with a scraper.

Use nail polish remover.

Oil maybe.

WD40 & Goo-B-Gone are my 2 go to’s for this type of thing. I’ve read that you can also use a hair blow dryer to heat up the paste & then use a razor blade to remove the softened paste, but I’ve not tried that one so I can’t speak to whether or not it works!!!

Use Goo-Gone in conjunction with a razor blade.

Some adhesives, like that from masking tape, are almost impossible to remove.

You might try some Goo-Gone, a bit of transmission oil (ATF) and some fine steel wool.

I use naphtha – zippo lighter fluid. That works really well.
Every house or apartment should have a can of it on the shelf.

If needed, isopropyl alcohol also removes adhesive.

Is oil not effective?

When using lacquer thinner or enamel reducer, or some other fluid that evaporates quickly, adding a bit of oil will keep the glue from re-adhering to the surface being cleaned.

Little update. Going to try the paint scraper. First tried with what I had. The closest I’ve tried is an ice scraper, but that was made out of plastic and didn’t do anything. Already tried isopropyl alcohol. Haven’t tried oil yet.

I’d try a razor first, @ScottyMcGeester. With a razor, you can exert subtle pressure and you will have more control over the razor, as opposed to a paint scraper which has a handle on it and will be more rough.

Meant to update this before but I finally got it out!

So I used a metal paint scraper first. . . and it managed to scrape off some of the residue but not all of it. Still messy. Used Goo Gone then and the paint scraper again and everything came CLEAN off. Perfect.

Thanks!

I find Goo Gone to be iffy most of the time. It works perfectly one time & NOT at all the next time!!! That’‘s why a friend suggested that I use WD40 & it seems to consistently work ALL the time. :)

Glad you found what worked best for you!!!

@ScottyMcGeester
I suggested oil because it’s the most easily available item, food oil or non-food kind.