It's a problem that plagues so many cat owners: cat urine in the wrong place. Anywhere but the litter box, and you have a major problem.
The first thing to do is address the cause of the inappropriate urination, of course. If you have a cat who is suddenly peeing in the wrong spot, the first thing you should do is take your cat to a vet. This is a classic sign of a urinary tract infection, which can be both painful and damaging. Male cats may also suffer from urinary tract crystals which can be excruciating and potentially fatal.
Male cats should always be neutered, and not only to prevent territorial marking (a.k.a. "spraying"). The same goes for female cats, who may otherwise urinate inappropriately as part of their hormonal cycle.
The first step to cleaning up cat urine is to find it. You may be surprised where the urine is, and how much of it there is. Cat urine will fluoresce under black light, and if you have a cat urine issue, I strongly recommend getting (or borrowing, or renting) a black light device for detecting cat urine.
