Peanuts (not the idiot "enviro-friendly" ones!) are a very viable packing material and I buy them by the 40 gallon bag full.
I've shipped a LOT of heavy stuff in them and the best way to do so is to PACK them in the box and by "PACK", I don't mean just toss the part in there with the peanuts, I mean make sure you have to struggle to close the lid.
My packages packed with peanuts leave here more rounded, than cubed and I've shipped some fairly heavy stuff in peanuts before.
If I doubt the peanuts by themselves, I wrap things in cardboard, or, in the case of large packages with heavy items, I layer, peanuts, then cardboard, then the (heavy) item, more peanuts, cardboard, then another item, until I get all I want in a package.
Numerous times I've shipped 6 connecting rods in a Large Priority Mail box, with peanuts and extra tape on all corners. Never a complaint.
Insurance for high value CAN make a huge difference in how it's handled.
I also Insure for the actual amount and I've shipped out $1400 in ECM's before with nary a dimple in the box, according to the receiver.
Recently I shipped a mostly complete 4bt P-7100 pump conversion via the "layered" method I mentioned above, not a problem according to my buyer.
I can tell you stories about RECEIVING stuff from guys on here.
Like the time a guy threw 6 common rail injectors in a box and shipped them...literally threw them in a box and shipped them, NO packing material whatsoever. He ate some $$ on that one. :doh:
I learned long ago that packaging makes sales and kills them, too.
I am NOT keen on balled newspaper for packing, I've done it on lighter stuff, but there is very little packing (compress-ability) value in balled up newspaper.
Old clothes kill me, they are a fool's venture, as is any other cloth. :bang
Air "pillows"? Forget about it.
Mark.