I think I have an even better way that is free and good recycling.

I use old tool catalogues. Currently I am using an MSC catalogue, at well over 1000 pages it will last me a long time.
I cut the catalogue into a more managable size on the bandsaw, leaving the spine. Magazine glossy paper is waterproof enough to mix up epoxy or filler and it won't soak through. After you are done you just tear off the page and throw it in the bin.