Rotten eggs smell is hydrogen sulfide and that is what happens when something rots in an environment of no oxygen, like a closed bottle. It is pretty toxic but I think can be neutralized easily with iron oxide(gfo) or sodium bicarbonate. I have not done this and it comes from the top of my head but I suspect some time with Google you can get a proper answer.
Perhaps someone in the gas industry could pipe up on how best to neutralize hydrogen sulphide.
http://en.wikipedia.org/wiki/Hydrogen_sulfide#Toxicity