what me and my friend use for filters are note cards works perfect cut off a little sliver and fold it in a zig zag and push in MJ a little tighter into the joint for your filter and there you have it.

works great i also use a roach clip when i dont feel like making a filter. my roach clip is medical clamps (perfect for it) than i usually drop the roach in a pipe and smoke it because the paper has the most thc and resin.

the notecard is more of a thing to keep you from getting burned than a filter and makes the air flow threw the joint a lot better, where with out one the end of the joint usually gets closed because of the wetness of you lips.