Mourning rice cooker

I miss the taste of baked sweet potato and decided to do it for the first time using the Oven. I started to preheat the oven to 400 F (no recipe, just play by ear), and totally forgot that I use it for storage, since I only used my oven once since I moved in. It wasn't long before I smell the strong bad smell of burned rubber, and that was the end of my poor rice cooker, which I use to make hotpot from time to time...I feel sad and a little mad, and wanted badly to call Hao and tell him what I did so I can feel less guilty, but his cell phone was off and he is in lake Paul, Arizona, enjoying fishing and boating fun. Well, before I tried to dial the number again after 30 minutes, I realized it is selfish to spread a bad mood around, and after all it was not a total failure, the smell of the baked sweet potato came out, (mixed with the burned rubber smell still), and it was not bad as the first try. Everything has a cost, I told myself.