Apply dish detergent directly to all of the dirty or debris-coated parts of your non-stick roasting pan and allow it to sit for five or 10 minutes.
Fill your roasting pan with hot, almost boiling, water until all of the debris you wish to remove is completely covered in water. Add a squirt of dish detergent and stir gently, then wait until the water has cooled enough to comfortably put your hands in.
Pour some dish detergent onto your sponge, then gently scrub the spots with the worst debris. Leave the hot water in the roasting pan as you do this. You should notice the top layer of charred materials beginning to come off, and some larger chunks of char and debris may fall off too. Keep scrubbing gently until the top layer of debris is mostly gone.
Pour out the dirty, soapy water from your roasting pan, then thoroughly rinse the pan. This will allow you to assess the pan’s current state and determine how close it is to being completely clean.
Repeat Steps 1 to 4 until the pan is cleaned to your satisfaction.