so the schoolslips are still sticking to the plastic file?
Cutting up that plastic file and laminating the whole 2 piece may
be your only way to save your document.
Or can the school re-issue another document which you can
laminate.
laminating machines are cheap nowadays. I had one and it was really
really useful. get one that does basic A4 size paper. If you can
get the A3 Lalminator, will be better.