What's that smell?

In the last 6 months or so I noticed a strong earthy smell when I turned on the water in my kitchen sink. I rinsed it well, ran baking soda vinegar and hot water down the disposal, read up on where the smell might originate. Nothing conclusive and I wasn't ready to accept it was some weird water standing in the pipes somewhere or some mildew growing in a hard to reach place. It didn't always smell, but was noticeable when I first ran the water. It was not the dishrags.

I finally figured it out. By mistake.

I was cleaning in and around my sink and scrubbing the rubber thing that sits inside the drain opening. It came out with the sponge into my hands! One look and I knew where the smell originated. Apparently our disposal is so powerful (YAY) that little bits of food and pulverized debris get tossed UP into the rubber thing instead of it all draining down through the blades of the disposal (BOO) and drain pipe.

So now I just have to regularly pull up the rubber sink drain thing (does it have a name?) that is supposed to stop a spoon or knife from entering the disposal, and scrub the gunk off!

Sorry no photos. Use your imagination.