I sprinkle a little baking soda to take care of "big stinky ones." The right scoop can help, too. I've got a big plastic one with a short handle that's good for scraping up the "pee biscuits" that stick to the sides or the bottom.

Also, if I see one of mine peeing when I'm getting ready to scoop (usually Don Juan, Official Litter Tester), I wait an hour or so, or overnight, so the biscuit will retain integrity when I scoop it.