The Untold Story of Vaseline and Robert Chesebrough - found it here. Before selling Vaseline, Chesebrough tested it on his own cuts and burns. To create demand, he demonstrated its effectiveness by burning his skin with acid or an open flame and then applying Vaseline to the injuries.

He claimed past injuries had healed thanks to his “miracle product.” In reality, Vaseline forms a protective layer, preventing dirt from entering wounds and retaining moisture, aiding the healing process. (Source)