Clay Bar Use

[spitshine1]

Hi Everyone First, I want to thank everyone for all thier help with my questions.

I am going to clay bar my every day use car.
I was looking at Mike's Detailing Handbook, I am wondering when i should start with a new piece of clay? How dirty should the clay get before i toss it in the can and start with a new piece.
thanks for everyones help.

[rider9195]

Usually when fold and kneed the clay and no clean sides come up its time for a new piece. I know Blackfire makes a clay cleaner and extender but I wouldn't bother.