Either ply it off, or get something that melts glue,(not glass), and apply it under the tank when tyhe tank is upsidedown. Or when you ply it off/after, you get an "exacto" knife and scrape it off. I dont think the idea is impossible, but it might cause dammage to the glass. :-l
You can get them off in one piece, but is usually easier if you cut it.
As someone already pointed out, the 1/8 inch glass used in ten gallon tanks cracks very easy.
I've tried solvents, but the silicone seems to yield to nothing but a razor and elbow grease, and a lot of patience.