I fixed the issue.
I used an wet cleansing towels (the ones you get on airplanes with your meal) followed by a dry cloth to clean every slider and pot. Then, I cleaned the side cheeks and wheels. But I did not open it up to do the wheels, so the parts inside not accessible would still have the residue. It is like new now, but it did take around 3 - 4 hours to do it as it took some elbow grease to get rid of the residue.