How do you open wine cork when it crumble?

The easiest way is to use a corkscrew which involves placing the corkscrew over the opening of the bottle with the latches on the sides facing upward. Twist the screw deep into the cork, then pull down on the latches on the side. The cork should come right out. If a corkscrew is unavailable, the task becomes pretty difficult, but not impossible. Try loosening the sides of the cork in the bottle with a sharp knife and then follow up by using any hook-shaped metal object to pry the cork out little by little.