hi, i have a nice carboy that i've used before with an improvised plastic bag cover. however this time around i'd love it if i could use the nice plastic lid that came with it and just stick a bung/carboy in it.
the bottle is PET, the lid seems to be labeled "PP", which is polypropylene? it seems very hard, here's some photos http://i.imgur.com/H2Ayf.jpg and http://i.imgur.com/DwEJ3.jpg
i have no real tools, but i can buy some cheap cutting implements if need be. just wondering if anyone has any suggestions for cutting a hole in this? it feels like if i tried cutting into it with a knife the plastic would crack and not be usable. it's probably about 5-7mm thick also... any ideas? or even any totally alternate ideas for a good extra wide mouth carboy cover?