[ser13]

I received a set of these pens (the retractable colored ones) when starting my first job out of college. I was teaching high school students. Unlike the early generations of erasable pens, these really do leave no trace on the page when erased. As a new teacher, it was excellent for grading -- students couldn't tell when I inevitably mismarked an assignment. Better still, the ink is heavy and dark, so my students couldn't tell that their assignments were graded with erasable ink. I can't recommend them highly enough as a hybrid between pencils and pens.

[chipsa]

> Conversely, the ink can reappear when temperatures reach below -10°C/14°F.

If they accidentally left it in a cold car, the mismarking will come back. Needs to be fairly cold though. Or a freezer.

[dec0dedab0de]

But if they happen to see them on your desk they could start changing their grades. Though I suppose high schoolers are less likely to bring every grade home.