disappearing ink pen hacks?

Best hack to use for diappearing ink pen?

I live in France and there is a pen from pilot who's ink disappear under heat over 60°celcius and reapears if you put it in the freezer . The pen is called FRIXION
rickharris6 years ago
1. I don't understand your question - if that is what it is.
2. What disappearing ink pen?
3. How are you expecting it to be hacked.

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