Cleaning your waste disposal unit is as easy as dropping some ice and salt or some citrus and vinegar into it, but there's likely one stinky spot you miss: under the splash guard. Here's the best way to clean it out.
The underside of your splash guard, or the rubber flaps in the drain that keep food and other bits from splashing back up into the sink when you run the disposal, is covered on the underside with bits of food that, well, just rot and smell in a place most people don't think to clean.
Clean your splash guard is with a toothbrush dipped in degreasing household cleaner. Lift up the edge of the splash guard and use the toothbrush to knock off or wipe away any gunk. Keep going until you've worked your way around the entire splash guard. Rinse the splash guard with cold water.
Of course, not all sinks have a splash guard like this that you can clean, but if you have a waste disposal unit in your home, it's a fair bet you do.
How to Clean a Garbage Disposal [Family Handyman]