Personally I think such a valuable piece should be professionally shipped. I looked into the best local shipping sources for large and difficult items to mail. The answer I was given was the painting needs to be crated. This company looks great http://www.gonavis.com/ . I think a crate is the way to go.
Have you ever seen those images online of the inside of a UPS truck at Christmas time? Very scary. Parcels on the floor, upside down, split open and bouncing it seems. So . . . . I phoned the buyer in Beverley Hills (yep, the 90210) and recommended the custom crate. Nope . . . . UPS ground is what he wants. I think my new boss (a local auctioneer) needs to state mandatory airmail and professional shipping on her website . . . . and that is my recommendation for immediate implementation. Ya!
But in the mean time . . . little ol' me is shipping a $10K antique oil on canvas painting.
I stuffed Styrofoam and bubble wrap all around the 3 inch buffer, on all four sides and then it was slid into another box for shipping purposes. Double boxed with hard board in between and 3 inches of bubble wrap all around.
Took me three hours to do!!!! So there ya have it ! The painting will be on its way today for its long journey from Ontario to California. Fingers crossed : )