Water Cooler containers - tops cut off. 'Greenhouse' use? (Hollingbury BN1)

These are water containers from a water cooler. They have an 18Litre capacity and are strongly made from Mylar.

I cut the top part of these off and have used them as liquid containers when making things like elderflower cordial. Now surplus to requirements.

Could be used for the same sort of thing, or perhaps as a tiny greenhouse or similar?

Collection from Hollingbury BN1 area by arrangement.