Ask the manufacturer. They surely have a help line.

Sure looks like corrosion. I wonder if the unit had been installed and used and returned. It sure looks like it.

HI -- Looks like mine which is mineral deposit from hard water . Scrub it with CLR . I also put baking soda and vinegar down about once a month to help keep it clean and not stinky . I also put egg shells in to sharpen the blades and it takes care of any food build up too . It's a plastic part so stuff is going to stick to it .

I was told not to put egg shells in the disposal, but I don't remember why not. If it's ok to do, then I can stop having a cow when my hubby throws one down there! I too use baking soda and vinegar, let is sit awhile, then chase it down with hot water. I also run the disposal with crushed ice to sharpen the blades.

Thank you all for the suggestions. I have another disposal (different brand) in my other sink that does not have this problem. Would mineral deposits or food build up like this so quickly? This is my first time using a disposal so maybe the answer is yes!