https://www.amazon.com/GC-ELECTRONIC.../dp/B00DJUHBIW

is the traditional material.

From "around the house", you might use any otherwise inert neutral paper or something like an index card.

The point of fish paper is that it is long-term, inert, resistant to puncture, non-flammable and all sorts of other virtues along those lines.

Peter Wieck
Melrose Park, PA