63StepSide:
Best of luck. When doing the front portion of the frame on my '66 Chevy C20, I cleaned it two or three times with Simple Green, as well as the Purple Industrial Degreaser from The Home Depot. At the time I didn't have a power washer, so it was all hand work, with good results. I now have a 3,850 psi DeWALT power washer. With the zero degree tip in the wand, I can strip paint off of metal. This will take the grime out, down to the bare metal.
In any case, using the degreaser and some elbow grease, you will get it adequately to apply the POR15. Make sure there is no residual grease, otherwise the POR15 will not stick over the long haul. I also let my degreased frame set out in the elements for a week or so. It developed a very light surface rust. I applied the POR15 over this light surface rust and it seemed to stick better on the oxidation better than the parts of the frame with the factory still applied.
I hope this information is helpful.
Tony
