How do I clean my gas oven at the very bottom where the burner is?

Last night I was baking a peach cobbler at 400F when my son noticed orange flames coming out of the vent holes at the sides of the bottom panel of the oven. I shut off the oven and eventually the flames went away.

After I let the oven cool off (next day) I removed the bottom panel of the oven (two little screws at the back) to reveal the oven burner. It was obvious that the flames were caused by the tremendous buildup of oil/grease in this area of the oven. I could see the black area where it had burned on the metal plate under the burner.

You would think I could simply clean this area and be good but it’s not that simple. This oven seems to have three layers of ‘panels’. The first is like the drip panel – the one I removed – that has the little vents on the sides. The second is below the oven burner. This one has a few large pill shaped holes cut in it directly under the burner and on either side of the burner revealing the third panel. This third panel is about 1/2 inch below the second one and is coated in grease. I see no way to remove the second panel to get to the third beyond disassembling the whole oven.

Take a look at the image. It looks like I poured a whole can of Crisco in there but I’ve never had a major spill. In the hole at the bottom right you can see where I’ve scraped away grease with my finger.

This oven comes with an ‘Alternative Clean’ feature which requires that I pour 1 1/4 cup of water in the first panel. How would this clean the grease out of the very bottom of the stove? I Googled it a bit and there seem to be a lot of people that think this feature doesn’t work at all.

I actually tried to replicate the orange flame situation by turning the oven up to 500F but it heated up and was fine. There was a little bit of smoke but it eventually went away. No flames. I’m assuming that I had burned away the combustible material yesterday but that it will eventually build up again.

So, how do I clean out the very bottom of this oven? The model # is IGL730CS0 Whirlpool.