burn off something
— phrasal verb with burn us/bɜrn/verb past tense and past participle burned /bɜrnd, bɜrnt/burnt /bɜrnt/
to remove something by burning it:
Until recently these countries were burning off gas they could not use or sell.
If you burn off pounds or something that you have eaten, you do exercise:
We eat too much and don't burn it off with enough exercise.