How do I teach our 3 year old to blow his nose?

maybe try to put some Vick's on his chest and see if that will help his nose run. then keep wiping it. i know he is 3 years old but maybe try using on of those baby nose things and try to get it out of his nose.. but keep showing him how to blow his nose he will get it sooner or later.. dont give up on him at all.. and maybe try to go to the store and let him pick out his own tisue box and see if he does it..