How to Clean a Caked-Up Oven with Vinegar
Before you begin, get some vinegar, a soft cloth, and a sponge. The sponge does not necessarily have to be abrasive, but it may be necessary if the grease does not come off.

The first thing to do is remove the racks from the oven and clean them with undiluted vinegar. Use a sponge to make sure you reach all the dirt, then soak them for about thirty minutes in a solution of two parts vinegar and two parts water.

In the meantime, soak a cloth in a solution of equal parts vinegar and water and use it to wipe down the inside surfaces of the oven. Use the sponge on the toughest grime, and add a little baking soda if the grease doesn’t come off.

Vinegar will also help prevent future grease buildup on the oven’s interior surfaces.

Once cleaning is complete, leave the oven door open to dry it thoroughly, after which the oven will be ready for use.

More tips for cleaning your oven
If your oven is dirty after you finish using it, sprinkle a little salt inside it while it is still hot. Once it has cooled down, it will be easier to remove the dirt with a cloth soaked in vinegar.

The outside of the oven can also be cleaned with vinegar, water and a soft cloth.