Is one allowed to cook food in a kosher pot on a non-kosher stove top?
A. Yes, by placing something in between (a blech, silverfoil, metal hanger).
Q. Is one allowed to use a tea kettle of a non Jew who only uses it for water?
A. Yes, if it wasn’t used for 24 hours.
Q. Is one allowed to double wrap food and heat it up on a non kosher microwave?
A. Yes, after kashering it – see here:
Q. If so, can I poke holes in it so the food doesn’t explode?
A. No, because then it is not wrapped.