Cat litter box stinks

So my boyfriend has a cat and he doesnt like to clean her litter box and it's in the kitchen and smells so bad and he has no sense of smell so he can't smell it I'm always asking him to clean it so we got some new litter for it for the smell but he hates it cause it clumping and he prefers non clumping we plan on getting a different kind so does anyone know anything that can help with the smell