how should I attack the rust in this area

Tadams said
This is the hood of my 65 barracuda. I need to take care of the rust. I can sand what I can see, but how do I take care of the area I can't sand.

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Mig up that crack and put a backer plate inside it to help keep it stiff, then ospho, works GREAT in those areas. pour it in the seams duck tape the holes and slosh it around so covers the whole inner area. it converts the rust , done deal.