My disc brake squeal cure
The front RS505's on my road bike started squealing at low speeds, like just before I would come to a stop. So I decided to fix it before they got worse. Did the pads-in-the-oven deal and cleaned the rotors with rubbing alcohol. They were instantly 100x worse, they would blow your eardrums as soon as the pads touched. The bike was unrideable like that. So I sanded the pads and the rotor with my dremel. No change. I cleaned the rotor with brake cleaner. No change.
Now at my wits end, I wiped the rotor with a soapy rag using Dawn dish soap (Walmart brand actually), I didn't even remove the wheel to do it. Then I got another rag with just water to wipe the soap off then dried it. Instantly fixed. For three rides now it's been 100% silent. I don't know if it was just using dish soap or a combination of everything I did but that was my fix.