Nostrum

nostrum \ˈnäs-trəm\ noun: 1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness, 
2. a usually questionable remedy or scheme; panacea {an audience eager to believe he had found the nostrum for all of society's ills — Warren Sloat}

Etymology: Latin, neuter of noster our, ours, from nos we

There is such a leap from ours to snake oil or scheme, there must be more to that etymology.