1. Remove all old shipping labels and tapes. That weight can put you into a much higher bracket.

2. If the box corners appear soft add some tape to resist crushing and to help it "slide".

3. All items "should" be double-boxed, especially heavy power supplies and sensitive items.

4. Tube rigs should be protected internally with newspaper or bubblewrap (never "popcorn),
to limit direct vibration damage and the shaking of tubes loose to then shatter.

There should be 2" of semi-rigid materials around the entire external perimeter of the package.