TIP: Ballpoint Pen

Got a ballpoint pen with a gooped up tip? If you're out and about, in the middle of something, or just don't want to waste a pen, try inserting the tip into a filter-end of a cigarette butt and twisting a few times. The material inside the filter is purported to be, hands-down, the best material to clean a pen tip.

Warnings: Don't try this with a fountain pen. Also, don't smoke a cigarette that's already been used to clean a pen tip. That would be gross, unlike inhaling what's already in a cigarette:

Cigarette smoke contains over 4,000 chemicals, including 43 known cancer-causing (carcinogenic) compounds and 400 other toxins. These include nicotine, tar, and carbon monoxide, as well as formaldehyde, ammonia, hydrogen cyanide, arsenic, and DDT.

From http://www.quitsmokingsupport.com/whatsinit.htm