No one wants to smell a pet before you see her, and I think cleaning up can be one of the trickiest balances to manage, especially for litter boxes. Many felines are finicky about which type and time they like to use and that doesn't always correspond with keeping the freshest scent.
I've recommended to sprinkle a thin layer of odor-fighting baking soda in the bottom of the box, but I'm curious which litter brand/box you use and if it could improve. So share your best litter products or tips to spring clean the kitty's box . . . and keep it that way well into the next season.