Re: Plumbing Help
I've had the old brass valves go bad and the solid copper tubes would gunk up right at the valve base. Replacing valves is a little more work especially if they are compression fit (not screw on/off). The new quarter turn valves seem to be better IMO. They have nylon inside parts and don't seem to gather calcium deposits as bad.
Could be just crap build up in the aerator but you said cold water is fine. That sorta takes the aerator out of the picture IMHO.