This is cool:
http://www.vinland.com/blog/?p=68#more-68
Someone has figured out that you can dissolve PLA plastic using Sodium
Hydroxide in an Ultrasonic Bath. Ultrasonic baths are super cheap, Sodium
Hydroxide is easy enough to get hold of. Sounds like it’ll be a great way
to add printable support to the reprap using dual extrusion.