I just bought a Worthington Pro Grade 4.25 lb. Empty Propane Tank from Home Depot to use with my Colemanstove.   The 1 pound cylinders are nowclose to 8 dollars a piece.   I was goingto fill it from the 20 pound tank but they say something about purging it.   Can I just fill and empty it a few timeswith propane vapor before trying to fill it with the liquid by inverting the 20pound tank?   I am guessing there is acharge to have it purged somewhere?

Gary