I've bought my pumice from Air Vol Block in San Luis Obispo, CA for a few years now. It's inexpensive there and good size, however there's al ot of white dust on it which clogs drain holes so I usually wash it. I use alot of it, both for collected trees and in my mix for Bonsai.
Generally I wash the soil on my slopped drive way out front. The white water flows down my drive way and along side the curb past a few houses and then into a street drain. Problem is this makes me a bad neighbor because the white chalky pumice powder is left along the curb when finished. Any suggestions about how to not make such a big mess?
The way I wash it is by putting a 5-6 scoops into my sifter and rinsing it until the water runs clean. Any suggestions on a better way to do this?