Getting spray paint off of glass can be quite difficult, but it isn't impossible. However, while doing it, you have to be careful because it can be dangerous. The easiest way is to take your glass piece and cover it in Windex. You can use other glass-specific cleaners, but we've found that Windex works best. You'll want to spray a liberal amount onto the glass. Your glass needs to be wet - not damp, but wet - the entire time you're working on it. So don't be shy about respraying regularly. Once your glass is wet, take a small razor blade held at a 45-degree angle and gently remove the paint from the glass. Be extremely careful not to scratch your glass or cut yourself!