I would seriously consider having it done professionally. By the time y
Out weigh in the time, materials and health risks, it is much cheaper to have it done professionally. I would do the whole thing. I would start by degreasing everything, then power wash, then blast. My concern would be driving the grease deeper into the steel. If you are going to use Imron, there is no reason to use por. In fact I think you might create more problems.