If you are into convenience over tradition & maximum kava extraction or just need some 'kava on the run', try this. Find some seal-able empty tea bags like T-Sac Size 2 (or larger) or Whole Foods carries Rishi which are even larger (look in the tea section). These will set you back about $5 or $6 per 100, or .05 or .06 cents each. Place 2 tablespoons into a T-Sac 2 (or 3 will fit into the Rishi) of the Kava of your choice (straight or blended). Don't overstuff them or they will have a tendency to break later. A lot of people seal these tea bags with an iron or one of those bag heat sealers, however I heat the flat edge of a butter knife over a gas burner for 5 seconds and then press the flat part onto the open end of the tea bag. This creates a super secure 1/2 inch seal strip. Store these kava bags in a nice zip lock to retain freshness.
Then when you are ready to use, just place one (or more) into a cup of cool to slightly warm water and using the back side of a spoon, press the kava goodness out against the glass. Just 30 seconds of stirring/pressing will create a nice 'mud' in a 12 oz glass (I only use smooth sided glasses, b-t-w to help protect the tea bag). I usually drink about 1/2 of the glass (about 1 shell) and then add more water and let it sit, then when I am ready for another round I stir/press again and continue the process until the kava is spent.
These tea bags are a super fine mesh so you get zero grit (although this also might be a bit kava wasteful) and you can't press like a mad-man either (I only have had one leak but I think I over filled it). However for portable kava that doesn't make you look like a voodoo priest or a kid making mud pies (kind of awkward in certain situations, like an office) this works great.
Bula.