Although my 2 english bulldogs dont do tht on evrything except dried leaves i still pull them away and scold them..hit their mouth at times when they bite or put something in their motuh when they're not supposed to and it WORKS!This is no cruelty or abuse as it is good for the owner as well as for the dogs to prevent from any harm or danger to the dogs as well!Good luck!Do it when they're still young as its easier to train them from young but it doesnt mean old dogs cannot be trained as well.
BULLYLICIOUS INC SAYS "MESS WITH MY BULLDOGS,GET THE SLOBBERS!"