Lost recipe from last year.
Here's an easy DIY cleaner made from baking soda, vinegar, and a few other household items you likely have on hand: https://www.apartmenttherapy.com/how-to-clean-your-kitchen-sink-136771
The easiest and fastest way that I've tried is to cut up a lemon and feed it through the disposal. The lemon will clean the unit and leave it smelling wonderfully fresh. :) Wishing you the best!
Here's what's worked for me:
Baking Soda and Vinegar. Turn on the garbage disposal and pour 1 cup of dry baking soda down, along with a cup of distilled white vinegar.
I just turn on the hot water, turn on disposal, squirt some dawn dish soap in it and let it run a few minutes.
Depending on what style your garbage disposal unit is, there may be stinky residue caught inside the rubber folds, or under the ledges.
Turn the power breaker off to the entire unit, then wearing protective gloves scrub it out with hot water and bleach.
Putting the removable rubber drain stopper in the dishwasher may help prevent some odours.