About about every 3 weeks or so, after scooping, I dump the remaining litter into a pail and thoroughly scrub and sanitize the sandbox. Then I use this stuff called Lucas Slick Mist on it. You can buy it at Walmart in the auto section, it's a detailing wax/ polish. It makes cleaning scooping so much easier as it doesn't stick to the sides or bottom then. It has a slight, but not offensive odor that disapates with in 15-20 minutes, the kitties don't mind it at all. I used to use paste wax, but found that the Lucas actually works better.
I also noticed the slight price increase, but it's not enough to make go back to that dang dusty stuff either. Besides, from chewy.com it gets delivered right to my garage where I store it anyway.