Oven cleaner?

[Kazbah]

I pull out everything that will move and clean it in a mixture of bicarb paste with vinegar (or lemon juice if I have any) and elbow grease. Glass with bicarb / vinegar. You don't need a plastic scourer - old pantyhose stuffed with newspaper will give gentle scour. Inside I use lemon or vinegar in hot water to loosen the grease, and then a bicarb paste to shine.

[Liz]

I think you did it about 3 or 4 times. So a couple of hours of just topping up the boiling water. But I think it loosens it well.

Lemon or vinegar sounds like a good idea too.