The oven is the appliance we only notice when it misbehaves. It sits there quietly accumulating a year of spitting roast potatoes and overflowing lasagne, and then one evening you preheat it, the kitchen fills with smoke, and the smoke alarm makes a judgement about your housekeeping in front of everyone. In the weeks before the heaviest cooking of the year, it is worth half an hour of attention — not for the shine, but so that the first roast doesn't taste faintly of the last one.
The good news is that oven cleaning is largely a waiting game. Almost all the work is done by soaking. Your job is to set it up, walk away, and come back.
Set it up the night before
Take out the shelves, the side runners and any trays, and put them to soak. A bath lined with an old towel to protect the enamel works well for full-size shelves; a deep sink or a large storage box will do for smaller ones. Hot water and a generous squeeze of washing-up liquid, left overnight, loosens more baked-on grease than twenty minutes of scrubbing ever will. If your shelves are coated or your manufacturer says they are dishwasher-safe, that is the easier route — check the manual rather than guessing.
For the oven cavity itself, make a thick paste of bicarbonate of soda and water, roughly the texture of toothpaste. Spread it over the interior surfaces and the inside of the glass, keeping it away from the heating elements, the fan and any vents. Leave it for several hours, or overnight if you can. The paste does two things: it softens the carbonised deposits, and it gives you something visible to wipe away, so you can see what you have and haven't done.
