It’s called burnt-on grease and carbon. It’s tough, it’s ugly, and it laughs at regular soap. You’ve tried the dishwasher, right? Useless. That machine is a liar. So, we fight back with science. Specifically, the science of soaking and scrubbing. But we’re going to do it the lazy person’s way, because that’s how I roll.
Before you start, grab your tray and take a good look at it. Is it non-stick? Bare aluminum? Stainless steel? That matters, but not by much. The trick works for all of them, just be a little gentler on the non-stick ones. No steel wool on those, please. You’ll scratch the coating and then cry later. I’ve seen it happen.