Single use WHAT?!?

I cleared out one of the raised beds and planted the garlic.
Lurking in the bottom, under the vegetation, was this; which I had, rashly, asumed to be paper when I emptied it l.ast bck-end
(Never assume, it makes an ASS out of U & ME)
I can't decide if it's aluminised Plastic or plasticised Aluminium, but one thing for certain - it ain't PAPER.
I'm very tempted to leave it & see how long it lasts. Like a prat i forgot and bought another packet, same firm. MUST remember for future ref.
* ~ * ~ *
The dead Kale stem BTW is to deliniate twixt 2 sizes of garlic:-
Normal : Elephant.