use a small electric angle grinder with a zip disc [thin] to clean things, also use a phosphoric acid wash to neutralize whats left in deep pits ... use
wide mouth vise grips on the edge bend, crimp it down a bit at a time ... spray the existing edge first with high zinc primer [cold galvanize paint], also the back of the piece you crimp over it ... use epoxy primer on the finished work if you can
Bill
