modern oak plank nail removal (0/1)

I've taken up some mid-60s oak flooring for re-use. The planks have L-headed soft nails through the tongue. Most are bent from removal. The L-head prevents pulling them through, the way they're set prohibits gouging them to get to the head.
Is my only alternative to dremel them off -- and beware during reinstallation.?
There are 3 pix attached showing the business end, the head set and the head exposed.
thanks for any ideas! Bryan
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