Plastic film, or clingfilm as it's referred to as in the United Kingdom is a thin plastic film. This clingfilm is most frequently used to seal food items for freshness.
No just put it in the freezer with some clingflim round it!xx
yes snails can live in a box with a plastic sheet as a lid (don't use clingflim) put a hiding area for them a water bowl and a food bowl. put things for them to climb over with leaves. feed them fruit and veg for food. :D