bath salts

[theotoky.livejournal.com]

(posting question only after looking in FAQ)

How do you get your homemade bath salts not to stick together?

I stir the recipe up in a big bowl; breaking up all the clumps, etc. Then I store them in an airtight mason jar. Yet, every time I go to use them they've fused together into a brick!

Thanks for your help!