I have lived in an apartment for 3 years. In that time, I could never get rid of a smell coming from the sink. I tried bleach, soda and vinegar, and bought disposal cleaner. Nothing worked. Three times I had them come to repair a leak, the fourth time, it was decided to replace the garbage disposal. Well, low and behold, no more smell!
So all the smell was from the disposal. I am a happy camper again. Hope this helps someone who "just" can't trace that smell.
They also sell these tablets that you drop in your garbage disposal....add a little hot water and it begins to bubble up right into the sink. It totally cleans your garbage disposal and takes all the smells with it.
10/19/2007
If your disposal stinks...usually of onions and such...just cut a lemon into quarters and run it through the disposal...cuts the odor, and smells yummy too!