It’s useful in the shop, too. Cut a length of freezer paper into small pages, pad them plastic-side-up atop a sheet of cardboard, and you get a great place to mix small amounts of epoxy:
Let the pad stay next to whatever you’re epoxying (like, say, the lathe tailstock ways), then test the leftover epoxy for hardness… rather than messing up the joint you so laboriously created by moving the parts an hour too soon.
Works for me, anyhow. Highly recommended!