When your residential or commercial garbage disposal begins emanating a foul odour, there can be a number of different causes. The accumulation of food waste in the disposal without regular cleanings can lead to a foul odour. In these cases, regular maintenance and filtration of your garbage disposal is recommended. Pouring residential cleaning chemicals like bleach in moderation can also improve the smell and resolve potential clogs. Other non-traditional methods include running your garbage disposal only using cold water. In any case, consulting a plumbing professional like Marvel Sewer and Drain is always the best choice.