Old gunsmith I knew used a trimmed turkey feather With just a bit of whale oil on it to give the lightest coating of oil on a trigger. Claimed whale oil never hardened and did not evaporate. I see it come up for sale on EBay for 200/pint. I know it must be fifty years old at a minimum. Surprised to see EBay let them list it. Ivory is long banned there. Hens teeth as well as common sense from DC is no longer listed.