I've used an icepick for years. I've blunted the end a bit. I probe gently, until I find the target, then move the handle forward and backward to make a slit. Then if I can't 'pop' the target out, I use a tablespoon, bent like a 'ladle' to dip the dirt out of the hole. I put the dirt on a paper plate. When I retrieve the target, I simply pour the dirt back into the hole, tamp it down level, and pull/push on the sides to get the grass-slit back together. It's a little slower than cutting a plug, but very seldom leaves a dead spot in the lawn. If I'm somewhere I can dig without worrying about killing the grass, I use a Craftsman screwdriver with thin, 9 inch blade.