Hi,
(1) "I microwaved my lunch box."
(2) "I heated my lunch box in the microwave."
Please correct these sentences.
Also, which sentence do you think is better, (1) or (2)?
Say 1) "I microwaved my lunch."
(2) "I heated my lunch in the microwave."
Both are OK. We also commonly say, in slang, 'I nuked my lunch', meaning in a joking way that I heated it with 'nuclear power'.
Best wishes, Clive