How to remove oil based product from windshield?

Hello fellow Elantra drivers,

I recently had work done on my bumper, and I believe there may have been some clearcoat or some other oil based product that spread onto my windshield. I've tried scraping it, my dad put window cleaner with ammonia, and of course, windshield wash liquid. All of these have not been effective at all, and the other day when I was driving through severe rain, the wipers just kept smudging the product throughout the whole windshield. Is there a product I can apply to remove this kind of oily substance?

Thanks in advance!