HI LOIS and welcome to the forums...
the decay on grab handles, tail light castings, UNcoated wheels or other metal bits...
is not exactly the same issue as filiform CREEP under the alcoa clearcoat.
still slathering parts with inhibitors PRIOR to the corrosion helps.
it's often faster to REPLACE rotting parts than repair them,
but for those wanting to clean, smooth and coat the casting, handles and tail lights, RC did a very nice job
see posts # 489 and 493 below...
basically this is accomplished by masking OFF the skin and sanding, smoothing...
then spraying with primer/inhibitor, silver paint and a coat of wax/sealant.
the hinges and handles can't be removed easily to DO this work,
but the tail light casting can be taken OFF to redo.