I just put on a set of new Cobalt rotors and went for about a 10 minute drive to be sure all was okay. After the drive I noticed the nice shiney rotors now had a bit of black gunk on the rotor surface... I'm assuming this is just some stuff on the rotor from the manufacturing process and will burn off after several days of driving.

Is this correct?

 

use some brake clean and a rag and wipe it off

 

did you clean the rotors before installing them?