Chrystalizing my brakes

So let me tell ya whats been happening. I just had the two front rotors on my 99 z71 turned. Put the rotors back on and drive around. Everything seems all hunky-dory for a lil while. Next day when i'm braking, i start to feel a clunking sound, not the same pulsating feeling from warped rotors.
I went to advanced autoparts and some fella says that i may have chrystalized my brakes. He says if there was to much gunk and crap on them, it did some weird chemical process. I'm post ta take me rotors off, wash em up with soap and water, then sand the inside of my brake pads.
My question is..... is this just urban ledgend? Is this for real? And how come only weird girls will go on dates with me.

24, studly, and available (to women only)

So i took off the rotor and cleaned it up, sanded down the brake pads and i've still got that clunking sound when braking, anyone know what that might be?

Loose caliper? Loose wheel bearing?