@cruiser, I agree with
@RustyRatRod and
@cudascott @missing linc on using a razor blade. I like the retractable single edge razor blade scrapers like you get at Target, Walmart and big box home improvement stores. Using these scrapers makes it easier to handle the razor blade and keep the blade at a constant shallow angle. I have had a lot of experience scraping glass. Please consider these ideas:
1. Clean the glass thoroughly first. You don't want to scrape dirt particles across the glass.
2. Use a lubricant of some kind. Windex works well, and so does a spray bottle of water with a few drops of dish washing soap in it (I really like Dawn).
3. Do a small area at a time. Maybe one square foot or so.
4. Keep the blade at a shallow angle to the glass. Also, move the blade across the surface of the glass at about a 45-degree angle. By that I mean don't move the blade up and down or side to side with the blade's edge perpendicular to the direction of motion. Instead, move the blade so that the blades edge is at about a 45-degree angle to the direction of movement. This will pretty much eliminate any chance of scratches.
5. Change the blade when it seems it isn't working as well as it was.
6. Be patient. It may take a while.
