I use a cup burr to smooth and round the end of earring posts.
followed byburnishing the whole metal earring in a rotary type
tumbler with stainless steel media. There are several sizes of cup
burs, so finding one for 20 ga is easy. I also like the cup burrs
made with slits in the side to allow the trimmings to curl away.
Another useful method is to heat the post end in the torch flame,
watchingclosely for the metal to just begin to melt. This one takes
practice and may not work for you.
Judy in Kansas, where the tulips need to be peppered to discourage