Aaron,
I did a quick Google and found this:
if this is baked on as you say, then it is probably not removable. The problem is the plexiglass, which is acrylic. If so, then any solvent that would melt the film, would probably melt the acrylic. You could try a small spot on the edge with some acetone, but if it is acrylic, acetone will go after it too. If your base material is lexan polycarbonate, it will be fine with acetone.The final method is to get a scraper or sharp blades and peel it piece by piece. But it is nearly impossible depending on the access or scratchability of the acrylic. As a last resort, Home Depot sells acrylic plates and you could probably replace them in the same amount of time as it would take to painstakingly fix them.Another good place to purchase is mcmaster-carr, do a web search and check their pricing for comparison to HD
Also found a suggestion to use Methanol
Good Luck.