I have seen several questions about cats not covering their litter properly but my question is just about the smell.
I have three cats, two of which are perfectly toilet trained but the third almost never covers, or covers badly when she goes to the toilet. Sometimes she just jumps out of the tray, and sometimes she will try to cover what she's done but she deliberately aims for the hard plastic of the tray edge, so hardly moves any litter.
If she's been to the toilet while I'm out, there is often a nasty smell throughout the whole house when I get home. How can I reduce or eliminate the smell, even if her toilet behaviour is still abnormal? The main issue is the smell, if I can get her to cover that should fix the problem, but that's not the only solution I'll accept.
If you have had a similar experience and have had success with a particular method, I'd like to know although "in theory" guesses are welcome too. I can only try them and see if they work!
Since the answers so far have all been along similar lines I feel that I need to clarify my question.
Cat poo is smelly unless it is covered. This should not come as news to cat owners! Very rarely one of the others cats will poo where they shouldn't such as in the bathroom basin or in the bath. Their poo smells just as bad and also makes the whole house smell bad.
The cat with the problem digs a hole and poos in it but doesn't cover it because of where she's scratching. So she's trying to do the right thing, she just thinks the best covering litter is the edge of the tray, instead of the unused litter sitting just inside the edge. She tries to scratch the hard plastic edge of the tray onto her fresh poo, instead of using the loose litter. So I either need to train her to bury from where it feels soft instead of hard or somehow deal with the smell of the poo sitting in a shallow hole.
This happens if the litter is a day old or if I have just changed it. She's not actually pooing on the side of the box, her aim when squatting is excellent, just like the other two. Only the poo touching the litter is odour neutralised. The poo exposed to the air just makes the house smelly.