I don't have any PUL, so I made do with a thrifted mattress protector. I am not quite sure what type of material this is but if it helps to keep your mattress dry from spills or accidents, then I figure it should keep moisture in- and not in the pail, right?
So how did I make it?
First I took a regular tall kitchen bag and used that as a guide to see how big I should make it. I cut the fabric out accordingly and zigzag stitched the edges.
Then I turned it right side out and sewed elastic to the outside opening.
When I put it in the tall kitchen trash can that I'll be using as a diaper pail (which I don't have yet) I will fold it over the rim just like a regular PUL diaper pail liner works. Like this one here...
If not, I can always just use them as regular laundry bags! Whatever the case they will not be wasted!