Last weekend I cooked a meal that really caramelized more than I expected it would in my french oven. It never got over medium heat and I let the pan cool then soaked it in the sink for about 30 minutes before using a wooden spatula to scrape it off under water. Would it have worked to leave the pan on the stove and bring water to a boil to dissolve it instead?
Like RP said, the best way is to clean the bottom is to deglaze it. If the dish does not call for it, I just put the pan in the sink with hot water and dish soap, let it sit and it comes off without even using an abrasive scrubber.
__________________ "Boldness has genius, power, and magic in it." Johann Wolfgang Von Goethe