I read somewhere that the impulse to vote more conservative came from the emotions of digust/revulsion & that polls could be skewed more progressive by simply cleaning up the polling place. Cant remember the reference off the top of my head.
Surprisingly the combo of citric acid & baking soda makes a reasonable rust remover. I believe it is a chelating agent....and yes, it does fizz everywhere when mixing.
Like Tal said, a confounder for that would be distances driven. There are probably similar ones like rural/uban populations etc. It would be great to see a study allowing for these.I couldn't find one but I didnt look very hard.
Its a bit of a trade off. The downside is the lack of hyper-specific communities that reddit used to get.