[jpr1968]

Well, that will be cheap and easy. I suspect I'll be able to limit the area blackened if I just dab it on with a q-tip. Tell me though, it rains pretty regularly in Portland; do you suspect I'll be fighting the same rusted areas over and over again as the vinegared area gets washed off? Thanks

It will only blacken the area where the rust is. You don't have ot worry about dabbing it. Coke and aluminum foil works good to.