This is what I started out with, an old and rusty metal vintage suitcase.
The first step was to paint the black sections with a chalky type paint, my own color using white and an olive green. It doesn't matter what color you use. Two coats of that paint did the trick.
The next step was taking care of those awful looking corner bumps. I used Burnished Brass metallic luster color. It went on rich and pretty. I also used it on all the other hardware of the suitcase, except for the metal edges along the suitcase.
The metal parts on the edges of the suitcase were painted with black acrylic paint.
And because I didn't want to leave it plain, I painted on some stripes. This would mimic the straps that it may have had at one time. I think this was the hardest part for me, getting those lines straight and not having any bleed-through.
But it was all worth it in the end. I now have this beautiful Metal Vintage Suitcase that I use to store my sewing items.