Assuming one has an old Yubikey, that needs to be disposed. The Yubikey contained some sensitive key material and you want to be sure nobody every could access it. For the record: Modern Yubikeys have a factory reset function, but we’re not in here for the easy way. We want to do it properly. By using an adequate amount of violence.

Stage 1: Using violence

Okay, long story short: use a drill and drill holes everywhere.

Mission accomplished. This method is easy and it will destroy the key, if you find the right chip(s). If you’re lazy as I was here, then don’t search for schematics online, but just drill holes until you find something that appears to be a control chip. And then continue to drill until you’re sure you hit them all.

So, that’s exactly what I’ve done here. If you look closely, one of the holes hit the main chip:

Be sure that you hit all the chips and you’re good to go. This is a safe method to ensure the chips are destroyed and it’s also an enjoyable way to do so. And it gives you peace of mind that the valuable secrets are not getting into wrong hands.

Stage 2: Being sure

At this point you can either trust that you hit all the potential chips, check online schematics (if they are available) or …

… use a grinder!

A grinder is able to reveal the hidden secrets of a Yubikey. Because those things are build to last. They are sturdy and difficult to damage or destroy. I’ve considered using a hammer, but I doubt without use of excessive force, it would do the job. Those things are sturdy, resilient and supposed to last.

However, a grinder is made to grind sturdy things:

This allows you to check if you hit all the chips and investigate the secrets of your now disposed Yubikey.

And this is how you safely dispose a Yubikey :-)