Laundry detergent is not the best thing to wash dishes. However, it is excellent at getting burnt food from off the bottom of a pan if you've accidentally left something to boil dry. Just add a couple of tablespoons of laundry to the bottom of a pan, add a couple of cups of water or cover the bottom of the pan, then leave to soak for a few hours or overnight if it's awful. All the burnt bits should lift away without any scrubbing!