If ur working with glass, nothing beats a razor blade. Just be sure u cleanse them cuz they come with a preservative layer of oil from the machining etc..So, I had some spots of tough algae on the glass and my scraper wasn't up to the task.
I ordered this:
https://www.amazon.com/gp/product/B01N8PUHKA/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Immediately realized the blades were too flimsy. But, it's stainless steel and easy enough to maneuver. The thought occurred to try a utility knife blade and it worked perfectly! They rust like crazy so I am ordering some stainless versions of them.
Very happy.