pauldw
Contributor
I've trimmed mine, but not with scissors. A sharp razor blade, after pushing a full plastic bottle (so it doesn't crumple) through the inside of the wrist seal so the seal doesn't wiggle around and there's something of a cutting board (tube) for backing. A larger jug for the neck seal. Make sure the spot where the cut comes around and joins the original start of the cut, is very smooth so it doesn't become an uneven spot more likely to tear.