We use this pan multiple times per week to cook beans. The pressure regulator has darkened and rusted and it no longer allows any steam to escape. This led to the rubber safety value popping last week, spraying our entire kitchen with boiling hot black bean juice. A lot of damage resulted from this incident. Without the regulator, steam escapes normally through the valve stem, it is not clogged. The regulator / valve opening must be defective. I tried scrubbing the regulator, no luck. It no longer allows steam to escape unless it is held in a tilted position. Be very careful when using this pan, always make sure steam is venting properly.