Would you consider using a vacuum sealer as a means of quality control.
What I'm suggesting is when one of us sends you a razor to be honed you could vacuum seal it, package it, and ship it off knowing that if it gets messed with a customs it will be obvious as the seal will be broken and if customs need to inspect it they can see all they need to see without breaking the seal.
also as a bonus it is hermetically sealed in case the package gets wet.