Hi Maria, there are lots of posts here:
Hi Maria: What I use is a paste of vinegar and cream of tartar (the dry stuff). Make a paste and put it on the gunk. Let it sit for about 15 or 20 seconds and then scrape off with a plastic putty knife or one of those plastic scrubbies. You may have to do it a couple of times if the gunk is thick, but usually not. A lot of people don't know, but on most stoves, the door lifts off and the bottom of the oven (the oven floor) also comes off, as do the rails on the side that hold the grates. You don't have to take the door off to get the oven floor or grates out. Sometimes it's hard to get the door back on:) There is no smell and it is environmentally safe. Good luck.