Do you just leave the code in the spot it was? Or do you move it up in the function comment? I've done that to also explain example use cases, and I've seen David do it in Rails core.
I'm not a Ruby programmer so maybe this is wrong for some reason. I leave it in place. With intelliJ you can collapse comment blocks so if you have a bad reaction to "messy" code you don;t have to look at it. Leave the corpse where it fell as a warning