I mix my kiln wash up in a 48 oz. pump up sprayer. (the kind gardeners use) I put in the amount of kiln wash I think I will need and then add my water. After lettting it set a while to get the powder wet, put the cover on and shake. If the consistancy is smooth and just a bit on the thick side, I pump up the sprayer and spray my molds or shelves.
If I have some left, It will store for a short time in the sprayer. Just shake, check the consistancy, pump up the sprayer and go again.
When the sprayer is not in use, wash the spray unit off and set it in the sprayer bottle.
Thanks for all of the great ideas!