How do I stop plastic from oozing when 3D printing?

Lots of 3D printing problems stem from plastic oozing out of the hotend, as everything warms up and the plastic becomes soft and begins to flow, gravity takes hold and molten plastic can ooze out of the hot end.


This is a companion discussion topic for the original entry at http://reprage.com/post/37966750340/how-do-i-stop-plastic-from-oozing-when-3d-printing