I don’t know the particulars of every nation, so I will just share my experience in sending packages to a few overseas.

I think it is fairly easy to put a chip in an envelope without it being easily determined. PROS: inexpensive shipping costs. CONS: No tracking info whatsoever.

Declare the package as merchandise: PROS: Tracking available. CONS: To get full protection for loss, you need to declare the actual amount of the item on your Customs Declaration. Don’t write that the item value was $10 on the form and later complain that the chip that was lost was really worth $200. Also, when you fill out the Customs form, the receiver in the other country may have to pay an additional tariff based on the value of the item coming into the country.

I have found it effective to send chips to the UK in a sturdy envelope as Registered Mail. Costs about $15, but you can track it all the way into the UK.