I am addicted to vintage italian cars and buy them, repair them, drive them, and sell 'em. I can't afford the Ferraris or Maseratis...so I deal in the cheap ones. My daily driver is always one of these (currently a 40 year old fiat). Because of this, I'm well acquainted with stuck nuts and bolts and all manners of rusted parts.

And my vote goes for.... PB Blaster!