How to Revive an Old Ballpoint Pen

5-15 seconds in a microwave (cap on). Wonderful! Here's how.

Start with 5 seconds (since microwave intensities greatly vary). Test the pen. Repeat a few times until the thing starts to write! (or ink is warm).

N.B. When you can feel that the ink is warm there is no reason it should not write (if the ball rolls). Liquid ink on ball, ball rolling; it will write every time!