If you want any postage service to handle your package with care, only "nuclear danger" logos and texts will serve you. Disadvantage is that several regulations deal with sending packages with these labels, so that might make things a bit more complex. So the best option indeed is to make the package bomb proof.

Don't scare me, I'll need the postal services for a big package in a few weeks...

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.