I wouldn;t use anything like boiling water of alcohol unless you're very careful not to get it on the good silicone that holds the tank together.
You need a stiff back razor blade (probably several) and a lot of patience. Be careful with the blade too as old/damaged/blunt blades can easily scratch the glass. I hope the tank was a very good deal because it sounds like a lot of hard work!
You need a stiff back razor blade (probably several) and a lot of patience. Be careful with the blade too as old/damaged/blunt blades can easily scratch the glass. I hope the tank was a very good deal because it sounds like a lot of hard work!

