I've use a block and med/fine sandpaper to get rid of the rotor deposits.
The stock pads CANNOT HANDLE a full track day at a more than beginner/intermediate level.
There is NOTHING like the Pgaids. Just phenonomenal. Love them.
No small wonder that like 80% of the ALMS/Daytona race teams use them and aren't even sponsored by Pagid.
Never a problem with rotor deposits running these beauties for years on my cars for track days. They aren't quiet though!
I go mine from him at
www.Rennstore.com