I use old fashioned waxed paper.
It may be too late but you should know that when epoxy kicks it goes thru' a "green" period when it is soft enough to shave off with an edged tool. Sanding wouldn't be my first choice because it is very easy to cut thru' the outer veneer without realizing it. If I had to sand I would use a wooden sanding block so that I could sand the high spots off without touching the wood. When I got close to the wood I would slow way down and try to get the last little bit off.

: Well I two hours in to my build and have my first problem. I used ziplock
: bags under my seams so the boat wouldn't stick to the wood. But guess what
: they will stick to zip lock bags. So what would be the easiest way to get
: the remaining zip lock bag pieces off my kayak? So I can epoxy that side.
: I thought about using my sander but don't want to take to much wood off
: the side. Oh and as luck would have it, the plastic stuck to what will be
: the out side of my kayak. And for future glassing what would be the best
: thing to place under the seams? I guess mylar but pygmy didn't give me
: enough. So any help would greatly be appriciated. Thanks Nate Lacy