The stronger the chemical, the less scrubbing needed. The most effective thing would be something like EZ-off oven cleaner (sodium hydroxide solution if you're not in US). You should be able to spray, let it sit, and wipe off, but make sure you wear rubber gloves as it can burn bare skin. If you don't like strong chemicals, I've heard people use baking soda+water, barkeepers friend, dawn dish soap, lemon juice, or vinegar. Other brands/types of oven cleaner/degreaser would fall somewhere in between the above two options, they don't vary too much apart from special cases like the EZoff

Be very careful. Those heating elements will burn the ever loving shit out of you in a split second. In a confined space it's like a game of operation. I'd try a strong oven degreaser and clean it cold. Honestly depending how bad it is it may be worthwhile to just buy a new one, and get said idiot a George Foreman grill while you're at it. Toaster ovens aren't multi hundred dollar like full ovens

Someone else = future me

Well it used to be included with 4G hence the name 4GAS but they removed it then changed the name to 5G so people don't realize it's not covered anymore

Look at Mr fat cat over here with his liquid nitrogen some of us can only afford gaseous

That's normal, you need to upgrade to the wireless heat package

Thank you for rewording my post to add the element of passive aggression

Edit: why are you booing me I'm right