In the past I have always just snipped them off with electrical side cutter pliers, and then bought new ones,
but I thought:
“maybe there is a slick trick to remove them and then re-use them.”
Side cutters are the easiest way I've found but I don't use them to cut the rivet. The side cutters will get under the head fairly easily. Then you just twist the side cutters side to side and the rivets usually pop out. I'm talking about the solid type...not the ones with the extra center piece that pops up.
