I had the same thing going on
in my navel
. All sorts of yucky stuff and this awful smell. It started after my endoscopic surgery. Dealt with it for years. The nurses all said to use alcohol to swab it out, but that never seemed to work for long. Only thing that did was to get prego. I guess 4 months of being REALLY open aired it out. (Not that I was prego for only 4 months, just only big open belly button...) Good luck, and as you can see lots of people have this issue.