Disappearing ink mystery solved

This afternoon I wrote a post detailing how notes in my notebook disappeared. A helpful reader sent the following:

You are right about the heat being the problem. Those "erasable" pens have ink that reacts with heat making them clear. Put the notebook in the freezer for a few minutes and I think you will see your notes again.

And... it worked. After putting my notebook in the freezer for 5 to 10 minutes, the ink again has color and my notes can be read.