The Makerbot Store sells two kinds of plastic: ABS and PLA. The former is a hard, durable, beautiful plastic, the same stuff they make Lego out of. PLA is biorenewable and biodegradable but far less durable. So, Dominik Wenger of Augsburg, Germany, thought, why not use the PLA as a support for an ABS fabject with an ordinarily unprintable overhang?
Currently one of the big problems of the DIY 3d-printers, is that nobody can use support with it so long. So many objects aren’t printable because of too long overhangs and other unprintable features. So it would be good to find a way to use a different material to print support structures which can be removed later. A friend of mine, a chemist, suggested that it should be possible to use PLA as support for ABS and dissolve the PLA later.
Judging from the post, it took a fair amount of work to get the PLA off, but it’s possible.