Probably a growing field of Products. Here's one source of stuff and ideas"

http://www.appropedia.org/Recyclebot

I've already collected all the parts for making a recyclebot, except the auger bit). But still have to go through 3 of the remaining filament spools to really need it I used two 1 kg spools in about a year and half printing quite a lot for myself, so it'll take a while... Also I know, - it will be a headache to print from the scrap plastic no matter how well the recyclebot will work. Most likely, instead, I will feed it with the commercial grade plastic pellets, they are about 3 times cheaper by weight than the ready to print filament - that should produce more reliable end product to deal with. But the scraps are still an option if nothing else is available but plenty of time to fiddle with them