Mean Green Mildew Destroyer works great, but is hard to find. I've used it on a white vinyl convertible soft top that had lots of mildew and it removed the mildew easily.
For anyone that might be searching this thread for a "one-size-fits-all" solution to mildew issues, there simply isn't one. Mold and mildew are living, breathing, evolving organisms and are not as predictable as we'd like to believe. Your plan of action needs to be completely dependent upon what the surface is that it's growing on. Don't be fooled by thinking that you've solved the problem just because you don't see it anymore, or smell it anymore. Work on small areas first, and test it with the least corrosive and most benign treatment you can find, like borax or vinegar. Work your way up to the heavy-duty, atomic bomb **** only if all else fails. Don't even think about mixing chemical compounds (you could die). Your mildew didn't just suddenly appear. It took a lot environmental gremlins to come together at just the right time, for it to flourish, and you aren't going to get rid of it permanently in a couplie of minutes.
Be careful using ozone generators. They do a good job of removing odour, but ozone is not good to be breathing. It is a lung irritant, and should be treated with care.
Some if you guys are going a bit too deep into this. Read the directions on the machine, they say to only use in an isolated/controlled area. Keep yourself and pets away. Common sense says to not place it directly on leather/vinyl seats. Set it on something like a piece of wood on the floor board. Only run it for a short period of time like 20-30 minutes. May need multiple applications. Mine has a timer, i set it and walk away for a few hours. Let things air out for a while. It’s not rocket surgery.
So now all the fake "patina" guys now have a tool so they can take the perfect leather upholstery and dry it out so it can shrink and harden!
Went out to the garage today and now the smell is back. As soon as the weather clears I'm going to have to do a thorough investigation.
The smell returned because you treated the symptom, not the disease. It's like trying to put a band-aid on cancer. If you have a natural fiber pad underneath your carpet, that's probably the source of your problem, NOT the carpet itself. Almost all carpet today is synthetic. You will need to replace your padding with an anti-microbial synthetic pad, or your issue will persist. Trust me ...