How do I clean a very dirty oven before turning on the self-cleaning?

Vinegar and baking soda is what I use. Or bite the bullet and use EZ Off oven cleaner.

Hi Arlene, I would get a towel very damp and lay on the bottom of the oven and let sit for about a half hour to soften things up. Then take a plastic scraper or you could use an old plastic card, spatula etc. and scrape of what you can before you do the self cleaning.

https://www.hometalk.com/search/posts?filter=clean%20oven

Check out any consumer complaints on using self cleaning mode with your brand/serial number of oven. Some brands have reported "fried motherboards"...a horribly expensive replacement.

Why not turn on the self cleaning and see how it does? If it doesn't get it all, then a second self cleaning. If there is still stuff left, try the wet towel method above. I say let the self cleaner clean! :)

My ovens that have had self cleaning do a really good job.