I know someone that has a Kirby vacuum and on the vacuum bags it says these bags utilize Kirby's exclusive "Micro Magic Particle Arrest Technology" to trap bacteria, dust mites, and other dirt particles down to 0.01 microns. So then I started thinking that this might be a good source of OTC high quality filter paper. I cut one of the bags open carefully and there was seven really thin layers of this "Micron Magic" paper. There seemed to be enough paper to make a decent amount of filters if all the layers where used by themselves. These bags are not that cheap when you get them from a Kirby store, but I see some real good deals for these bags on a major action website most of the time... and considering the amount of paper you can get from these bags it seems well worth it... if it works well as filter paper that is. I haven't used them for filtering anything yet, but SWINM is going to filter some RP solution through these soon and see how it goes. Maybe someone else can try these before I do and report your results also.