Avoid ammonia-based cleaners as they smell similar to urine. You can make a deodorizer using one part vinegar to one part water. Commercial deodorizers are available through pet supply stores and veterinary offices. If your cat is spraying If your cat is unneutered, he will almost certainly spray. This is just natural cat behavior.
Neutering is the first step to eliminate spraying.
In the vast majority of cases, neutering a cat who sprays will eliminate the behavior almost immediately. See the PAWS brochure on low-cost spay and neuter clinics. When neutered cats spray, it is almost always the result of an aggressive or competitive relationship between two or more cats. A new cat can stimulate an aggressive reaction in the resident cat. Also, indoor cats may react to the sight or scent of outdoor cats by spraying.