Specifically, it's proteins that set and harden with heat. Oils come off trivially in the dishwasher (unless they became polymerized through heat, a common proc

Specifically, it's proteins that set and harden with heat. Oils come off trivially in the dishwasher (unless they became polymerized through heat, a common process on pots and pans). The other variable is the time the dishes sit dirty before the dishwasher gets turned on.