So I collected our bags + others from the folks we were visiting and started cutting. I cut the bags in one long spiral strip. I find the best way to do this is by cutting off the top handles and bottom of the bag so you are cutting the strips from a long tube. I also like to cut up a bunch before I start to knit. Cut the strips about ¾” to 1”- it doesn’t need to be perfect!
You can knit plastic bags just like anything else.
I have made a bag of plastic bags before and the best method I have found is to first knit a square for the bottom (mine is 6 ½” x 6 ½”). Keeping the bottom stitches “live” (don’t cast them off) proceed to pick up stitches along the other three sides of your square on circular needles.
It is best not to make it too loose a gauge. I am working on 10 ½ needles and getting about 4 st to the inch. The bag will stretch a lot once you put things into it!