Combine meat tenderizer, celery salt, seasoned salt, and garlic salt in a small bowl. Rub spices into brisket. Put brisket in a large heavy duty Ziploc bag. Add liquid smoke and Worcestershire sauce. Seal bag and put in the refrigerator to marinate overnight.
Add water and BBQ sauce inyour VitaClaypot(VM7900 or VF7700). Add brisket and any juices in the Ziploc bag (put the side with the fat on top).
Cook on "SOUP" for 2 hours.
Serve with additional BBQ sauce mixed with some of the cooking liquid.