I saw somewhere on the internet that if you have cork clay you should always fire at 1435 for at least a half hour.  Seems to me that by the time you get up to temperature, the cork is gone (at least there is no more smoke).  I cannot find it written down anywhere and am wondering what the factor is.  If you would fire (hold) for 10 minutes, would this also work to burn the clay?

This information is from artclayworld.com:

Firing
Art Clay that is fired with Cork Clay must be fired with a kiln, and at a lower temperature. The lower temperature is especially important when using significant amounts of Cork Clay. The danger of higher firing temperature is that when the cork burns, the air in the kiln may superheat, causing the internal temperature to rise close to, or surpass, the melting point of silver. This extra heat may result in damaged or distorted pieces.
Firing with Art Clay Silver Standard: 1472°F for 30 minutes
Firing with Art Clay Silver 650/1200: 1200°F for 30 minutes
1290°F for 15 minutes
1380°F for 10 minutes
1435°F for 5 minutes

 Remember to dry the cork THOROUGHLY before firing!
 

Thanks.  That makes a lot more sence to me.  Art Clay World is one of the sites that I went to but wasn't able to find what you quoted.  I have it now though, thanks.

Sorry for the typo - should have said makes more cents. (since?, sense).