Use a better premium clumping litter, i found, by my personal opinion, Arm and Hammer Litter pretty good, no dust or any odor, if you use a covered litterbox, or from what i have been hearing, worlds best cat litter. But here's a trick to make a litter smelling clean, put 2 or 3 cups of baking soda and mix it with the litter, it'll soak up the smell, and seems, but i might be wrong, improves clumping power for urine and seems to contain the smell.
maybe something is wrong with your cat's diet/food.
BUT i have heard of training your cat to take its business to the toilet. It was featured in Maxim magazine, it was kinda weird to find a cat tip in a men's magazine. If you have more than 2 bathrooms it is worth the trick if you have to give up that bathroom for the cat.
I remember it quite well.
Before doing this put the litter box in the bathroom you are using so the cat will know where to take its business. You might have to place it a week or 2 maybe more before the actual training so the cat will be accustomed to the bathroom.
1. For the first week or two place the litter box on top of the toilet, seat down/cover up. (I dont think it makes a difference but try first week covered and 2nd week seat cover up)
2. 3rd week - 4th week (if cat is picking up exceptionally well)
Use cling wrap to wrap the seat (cover up) make sure it has slack to hold the litter (fair amount) Poke some thin holes for some urine to get thru. Gradually reduce the amount of litter. Observe the cat to see if it is comfortable with the seat.
4. After the cat is confidence with the toliet techinque, put some litter in a ziploc bag with some holes (placed behind the toliet seat, the gap between the seat and the tank ) so the cat can smell the litter, if the training pays off, your cat will be actually using the toliet instead of a litter box. Try training your cat to flush! that would be an added bonus!! lol
Important things you should do:
Be sure the bathroom that you are using for training is undisturbed until training is complete or try to get the cat used to people during their elimination. but people dont stay in bathroom all day do they? That means you gotta sacrifice your bathroom for a month or more.
Also observe how your cat does its business, it should be sitting on the seat the way we do. I think it shouldnt be a problem for females, but i have never seen a male cat pee. not sure if its the same direction as females pee, but do expect some urine splatter from time to time.
And most importantly be patient!!!
Let us know how it works out!!!
Hope this helps.