Yeah the PB-blaster & Kroil no longer get ANY attention after discovering this technique. The only penetrating oil I use now is seafoam - used primarily as a cleaner. I got sick and tired of snapping bolt heads with a torque wrench only to spend hours drilling them out and re-tapping things. Obviously heat can work wonders as well but for H20 is a damn miracle on rusted/seized bolts - It'll even help break bolts that have been torqued tight with yellow or blue locktite, so long as theres rust present.