You can blow the lines out with compressed air, as outlined in your owner's manual. I don't think hydrogen would be a good choice, it could give a new meaning to "blowing out the lines". Vinegar smells worse than RV antifreeze. Some people use alcohol to winterize. Vodka or Everclear would probably have the least odor.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.