Avoid Ammonia Based Cleaners
It is natural for dogs to soil their living areas. This can be avoided by letting them out at specified times and not letting them in until they have urinated. If your dog soils the crate, it is not reason to scold or punish him. Maybe, he was not trained enough. Just get him out of the crate and clean out the mess.
You will need something that will eliminate the odor of the waste. Definitely, it will not be an ammonia-based cleaner because ammonia has the smell that will remind the dog of urine. It might only make him associate his crate to a place where he can urinate. Rather, you can use a dilute bleach solution, or a half-and-half mixture of warm water and white vinegar. This will work for all kinds of crates, small or large dog crates and crates made of plastic or metal.