The one thing to make note of here is Dawn is NOT oil-based. Dawn is soap (or more appropriately, a surfactant), and soap is basically animal fat + lye. Dawn, specifically, is a surfactant that is actually soluble in water, which oils are not. Furthermore, it is a "water wetter" and can actually be mixed in small parts with water and ethylene glycol and run through your car's cooling system.
Wherever it got out that Dawn was oil-based, that isn't true.
Oh by the way, the dishwasher method works best for me.
Jess