Need some junk plastic for repairs

Hi, looking for some plastic pieces, maybe 2"x2". I need it to aid in re-attaching my dash lenses in my 69 cuda bezel. If im correct, you just can "shave" thin strips and mix it with a small amt of acetone correct??

Thanks
4spdragtop

A member on here used cassette cases for the plastic. I remember some pictures and it looked great but I don't recall which thread.