Have you tried scrubbing It with an SOS pad Terah. I use these a lot to clean my older baking pans that are NOT nonstick-the SOS pads will scratch a nonstick cookie sheet. It won't quite look like new but you can get them a lot cleaner.
Hi Teray: 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. There is no smell and it is environmentally safe. Then, you can shine it with an SOS pad, but rinse it really good after that. Good luck.
Soak in a solution of blue Dawn and hot water, maybe boil a pot of water.
You can use several different things to get build up off:
barkeeper's friend and steel wool or emery scrub sponge
marble paste and scrub sponge
baking soda and hydrogen peroxide in a paste
Bit of fairy an a wire spounge. An elbow grease :)
Send it to my 90 year old Italian mother. She can get anything clean. Lol
hometalk has some ideas: