take it off, bang it out from the other side as well as you can, buff it on a polishing wheel, and you will get as good as you can.......still might see some sort of defect, but not as bad as it is....
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A round face plastic hammer, and some soft wood to back it up might work best.
I have never done this or seen it done, but I was wondering, would it help if you heat up the metal before you hammer it, or would that ruin the chrome?