After drilling in metal there is often a large bur around the hole. It’s unsightly, dangerous, and can throw off how your piece goes together.
Eliminate it easily by using a drill bit that’s larger (by far) than the hole you’ve drilled.
Chuck the large bit up into a pin vise. Place the metal, bur side up, onto a surface that allows the tip of the drill bit to drop down through the hole. I usually just place the hole over the V in my bench pin, or slide it off the edge of the bench, whichever is easiest. Press down firmly and twist to remove the bur.
Caution Don’t go all the way through or you’ll be left with a hole much larger than you intended.
Lightly twist back and forth a couple of additional times to clear the swarf and you’re done.