Radarman, I appreciate your contribution to this odor thread. Hope OP will forgive me for a bit more off topic-ness but I hate to start another thread just to get some clarification. I had a horrid grey smell assault me driving out of high elevations while raging forest fire smoke from Yosemite forced us to turn our AC to max (inside air). It was horrible. I figured out the smell was emanating from the AAVs so to prevent dying from noxious fumes I put a plastic sack over them till we got home. We dumped the grey and did a mini GEO on it, no ice, powdered arm and hammer since no calgon was readily available, and added a cup of dawn. It got the tank good an clean. Today I removed the Baggie, unscrewed the AAV from the kitchen and it appears to be patent. I washed it good, then blew in it. No air got past the rubber disc. Sucking on it it worked fine. Seems okay. So I am wondering just what happens at 7000 ft. On a hot day? We got some walex brand lemon stuff at CW and it worked for a while. Today, a week after adding it, I was cleaning up at our storage site and I could smell it through the baggies. Uh oh! I added a bunch of water to each p-trap and it seemed to help. DH went to Home Depot. They had no idea what the gizmo was and my guess is they are not sold here in California since they don't meet code standards. Plumbing.com has them. I read at RV Doctor that they can be lubricated with Dow 111. DH can bring some home from work Monday. But TBH, the one I took off for him to take to H.D. seems to be fully functional.
Can you shed any light? Incidentally my Sealand Dometic toilet has no such trap hole, and I gave it a thorough on-the-knees cleaning today. I sure hope OP got rid of smell.