Hi go to Wilko's and buy the oven pride for £3 and you can do it yourself, it's easy. There are a pair of gloves ,a very large bag and the cleaning liquid . Always have the gloves on and take out the shelves and place in the bag pour 3/4of the liquid in and seal the bag. I left my bag outside over night to soak.(my were real dirty I'm ashamed to say) Then with the rest of the liquid coat the inside of the oven and level coated my glass and leave for a few minuets . Fill a bowl with hot soapy water and get a nonstick scourer and get the splashes of the glass, it comes off easy. Wipe the inside of the oven with the same and then rinse with a hot cloth. Next day take your rails out of the bag and rinse in soapy water . You will be amazed how clean they are and the disgusting liquid that is in the bag. Throw that away and stadium back, to admire your brand new oven. Cause that's what mine look liked. Just £3.00 and it's not difficult . I now roast meat in those roast bags.....