Questions & answers

Hello,

a few minutes ago, I noticed a faint smell of burnt  plastic. I went to the kitchen and found that our maid was cooking chicken with this vessel (photo) in the oven. I told her that the smell must come from the plastic knob (the oven temperature was 220 degrees) but she insisted that AMC has special plastic knobs that can go into the oven and that she has been using it that way forever.

I remember hearing something like that for amc pots but still I couldn't detect another possible source for the smell.
So I am asking you:
Do these things have a temperature limit? 
Could it be that with age, they become less heat resistant? (these pots are about 3 decades old, maybe more).
This is by no means a complaint. I am just worried if we are using it safely.
thank you very much!