A/C works fine, no noise from compressor or clutch.  When it cycles on
and off, still no noise.  However, when turned off I hear a shrill,
sorta grinding noise, and can see little metal flecks beneath the
pulley.  It's got to be the A/C clutch but don't understand what's
happening.  I assume it stays engaged as the thermostat cycles on and
off, but why is it self-destructing when the system is completely
turned off? ---Bob