It was 2 weeks ago now that I had my last couple of session in NY in my 5/4/3...the last time I used it I left it inside out hoping it would be dry when I got back out in the water later in the day but it didn't pan out, and so it was left inside out for a 10 days. When I turned it back the right way, it wreaked like hell, so I washed it in the shower, but to no avail. Then I let it submerge in a soapy tub for a while yesterday, but the stench seems to be stronger, and pissed. It's taking over my apartment like the Beast did to Seinfeld's car.
I use Wool Lite when I was mine then dry it inside out. Seems to do the trick. My booties don't even stink that much, amazingly. About every 3-4 sessions I give my rubber a good washing with the lite and does the trick.
Sometimes hanging it in the direct summer sun is all you can do. A day inside out, a day outside out, and you should be good. Normally, direct sunlight is not a good idea, but in cases like this you just have to. No worse than a day surfing... Keeping it wet (especially with saltwater), dark, and warm is the worst thing for creating The Stench.
Other than that, try a product like Sink the Stink, with the activated enzyme that kills the bacteria that creates the foul smell.
BTW... that presence of that bacteria also indicates that your suit is rotting, so killing the bacteria is more than just a "cosmetic" issue.