OH, I got it.
When he went there, Chesebrough noticed that roughnecks who worked the rigs were maddened by a gelatinous black gunk that clogged up their drills. They called it “rod wax” and were constantly having to wipe the stuff away. But these same working Joes, Chesebrough was interested to see, slapped “rod wax” on their cuts to help them heal faster.
Chesebrough took some jelly to his lab and tested its healing property on himself. It worked. He soon had a fleet of wagons trundling around the country distributing Vaseline (a barbarous combination of the German “wasser”, and the Greek “elaion”: “water-oil”).
Chesebrough was an evangelist. In front of rapt audiences he would burn his skin with acid and then anoint the wounds with his wonder-jelly, pointing to earlier scars Vaseline had healed. Next day, every druggist in town would have bought a wagonload.