Cob: commercial clay

[~Lootvik~]

Here in SoCal there's a brick plant where people get different colors of 
clay, by the truckload.  Outside a town called "Corona."

>I gather most people are using clay dug on site.
>
>Has anyone tried using clay from a brickworks or some other industrial
>supplier?
>
>Or are people getting clay from some building excavation site?
>
>I live in suburbia and don't really need to dig a big hole in the ground.