i dont think you need to use very much at all. id put maybe 1/8th vinegar and the rest hot water to wash it. then rinse it well with hot water.
i dont know if thats the best method, someone here might have a better suggestion for you...but im pretty sure thats the amount you could use. Oh and its not like its poison so if you used a little bit too much it wouldnt do no harm...just as long as its rinsed well afterwards.