Long-term cat odor
Friend of mine just bought a house. Well, a trailer... Well, a sort-of house, consisting of an addition to a trailer... well, an addition next to a trailer. It's kinda hard to explain.
Either way, the former owner had cats. Lots of cats. Lots of cats which he didn't seem to take much care of. Several of the cats are still here - they were living in the walls and kitchen cabinets when my friend moved in. He had the humane society come and trap most of them, but he kept two, which he's managed to convince to actually live in the normally-occupiable parts of the house, rather than in the walls/cabinets.
Meanwhile, parts of the house smell like cat urine and feces - bad. It seems to be soaked into the carpets and floors. Is there any way, at all, to neutralize/eliminate this odor, short of major carpentry and replacement of the floors?
If I remember correctly, bleach works fairly well, but I'm pretty sure it'll do a number on the carpet in the process.
Is there any chemical, available to consumers, which will remove cat odor without simultaneously destroying the carpets, tiles, and/or plywood?