I was taught 30 years ago how to remove KO's from panels and it has never failed to work. I, on occasion, have used other methods because I could not find the tool I use. Once I fought with the KO I found the tool.
Dykes. I don't know what to call them besides dykes. I guess wire cutters the pointed kind. I first knock out the smallest ko then take my dykes and cut each side of the next ring midway between the Die nub. Then just grab the Die nub with the dykes and waggle off each half of the ring. This works every time all the time. Any other method creates all those problems.
Try it you'll like it.
Tom
