On Thu, 23 Jan 2014 19:44:53 -0500, "Steven L." wrote:

My kitchen disposal is giving off this bad musty odor. And it's murder
on my sinuses. Every time I go near that thing, my nose stuffs up. I
know the odor is coming out of there, because if I cover the disposal,
the odor goes away--but the moment I uncover it, the smell is there.

I cleaned the disposal but the smell remained. Even using full strength
Clorox only kills the odor for a couple of days, after which the odor
returns. There's some black gunk under the rim of the disposal. I
scrub it off and bleach that area, but the gunk returns in 48 hours.

So now I'm wondering if there's decaying material either under the
rotating plate of the disposal, or perhaps even deeper into the drain
pipe, from which bugs keep growing. I tried Liquid-Plumr to dislodge
any gunk in the drain, and the drain flows freely. But that didn't help
the odor either. Or maybe there's bad stuff in the dishwasher drain
hose that feeds into the disposal???

Any ideas?

Before I replace the disposal, I want to be sure the problem is there
and not in the drain itself.

Unfortunately, the only thing you can do is disassemble the drain pipes under
the sink, especially the trap and clean everything out. I recently had
something like this happen only to discover several of the pipes under my sink
were 50% clogged. I used a hole saw on a long arbor to clean them out after
taking them apart.

Could you have debris stuck in your disposal, yes, it can happen, but you have
to take it apart to fix it.