Some people have no clue how to pack things for shipping. I sold my wife’s mother’s collection of Wedgwood figurines some twenty years ago when you could get decent money for them on eBay. Some sold for $500 each, I packed them and mailed them, of the twenty odd items I sold none were broken on arrival.
Shipped items have to be in sturdy boxes that can take a beating, the part must be wrapped in multiple layers of bubble wrap and tightly bound, The gaps between the bubble wrap and the box should be filled with styrofoam tightly packed so that when the box is shaken the item inside does not move. The thickness of the packing material depends on the strength of the shipped item.
I would ship a third stop light in a schedule 40 plastic plumbing pipe, with end caps securely taped on. The part packed securely with polystyrene at each end. The packing is going to weigh more in this case than the part but it will arrive undamaged.
Popcorn is pretty useless as unless it is jammed between the box and the wrapped item it will get shaken all over the place.
The handlers at the post office or whatever do not really care about your parcel, they arrive on a dump truck and are tipped onto the concrete floor like a load of bricks. They are not taken off individually.
Parcels with “Handle with care” labels are liable to be treated with less care, particularly in times of labour strife or if handled by a guy with a chip on his shoulder in which case your parcel could end up chipped.
The box shown in the previous post is a joke, rectangular boxes are weak, round and triangular boxes are stronger. Some shippers do not take round boxes as they roll around too much, if so put it in a square box.
Put the name and address of sender and receiver on the box and the wrapped item and if it is worth it insure or at least have tracking on the parcel.
It’s a jungle out there, only the well packed survive.