Jothar- Oops! I forgot about hamivatel bishvilo. Thank you.
Regarding Pizza- I have heard this shaila raised in E”Y and it was permitted. You are not doing anything by throwing the pizza in the garbage. Its not likely that its still yad soledes, its not derech bishul etc… The shaila would be when the garbage is incinerated that you have real bishul; but the Poskim were matir anyway
yitayningwut- I am refering to the general rule with all keilim. We never say the kli is shishim times the contents. (The reverse may be possible with a wide pot) However, with a kli ???? ?????? ???? you still may be allowed to use it.
Ovens- I cant recall ever hearing of anything of this sort. Can you please explain the logic behind it?
Ragachovers Assistant & yitayningwut-
??? ???? ???? ?? ??? ???? ????? ????, ?? ?? ?? ??? ??? ?????? See Taz 92 Ois Lamed and Shach 107 Ois 7 that discusses this.
What I have heard l’maase is that the first couple of times we can be meikil, but after that we would consider it a kli rishon.