Removing paint from glass

I just bought it about 2 hours ago, so, so far I haven't tried anything yet. I'll try out the razor blade after I hose it down to clean all the dirt and stuff off.
 
razor blade. they make a handle for the razor blade that kinda resembles a squweegie. You can get them from any hardware store floating around in the paint or caulk sections.
 
I am a window cleaner and unless the glass is tempered, which fish tanks generally are not, a razor blade will not scratch it. Go to a janitor supply store and pick up a 4 or 6" razor ($10-15). Just wet the glass with a little soapy water for lubrication and go to town. You can press as hard as you can and it will not scratch the glass. Just be careful to keep the soap out of the tank.
 
A razor blade.


^^^ Yup.
Just keep the blade clean and clear of any excess paint or odd bits that might scratch the glass. Helps to keep a very small angle, too. Like your finger nail touching/pressing on the tank w/the blade back right over it.
 
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