Try Mr. muscle spray on oven cleaner. Spray then leave while you clean rest of house. Take shelves outside, spray and leave. Then use hot fairy liquid in water, green scoured etc. Then use glass cleaner on door. Time consuming but better than your method. Little toothbrushes and small screwdrivers help too. Good luck, we do about 70 student houses like this. Don't forget the grilles in oven hoods, thick with grease but fairy liquid is the best and we use Ubik.