This reminds me of another old trick on how to heat treat brake rotors. Clean the oil off of them, heat them to about 300 degrees F, leave the rotors in there for about 30 minutes, then turn the oven off and let them cool gradually. Repeat once or twice if necessary.
This helps keep the warping of the rotors to a minimum when installing new parts.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.