You can also put a piece of thread in a coping or jeweler's saw frame and it will cut plastic. I know it sounds goofy and you won't believe it till you try it but it actually works.
Thats just like in my glass profession we use steel wire to break the glue seal on front windows currently, but they are now switching to a fiberous line its like a hyped up high tensile fishing line almost!! it will go thru the glue, but if your not careful that "string" can still cut through metal pinchwelds on vehicles!! yikes!!