coincidentally I just happened to finish folding some laundry before logging on, well for me this is a winner
On a serious note back in high school I used to use navel jelly and elbow grease to clean up areas before re-primer and paint if pulling a body part or part was not an option to cabinet blast and then primer/paint.
The POR15 primer/paint in a rattle can, chassis black have worked well for my recent parts/chassis touch up.
Looking @ your picture...that looks beyond blasting and cleanup. If you blast that you will probably have not much "real" metal left and probably expose a very unsafe frame ect.