[GravityFog]

I prefer to just cut the middle part of a soda can, roll it into a cone and then tape it onto the end of a hollowed out BIC pen - perfect for a makeshift slide. So long as the hole at the bottom of the cone is small enough, no need for a filter at all. If you roll the cone right, you won't have to worry about burning any paint off of the can either, just make sure there's no excess can rolled into the cone and you're good to go, stick that shit in a water bottle.

Of course, I prefer glass.