An interesting idea. It certainly wouldn't take up much room, and it would probably burn easier than a rag filter. The real question is how does it stack up against waterproof paper? Can you write on it while soaked? Does it hold up in harsh conditions as well as Rite in the Rain? I'm thinking those are the main concerns with small scraps of paper in your PSK, since a comparable filter could be fashioned from a piece of clothing.