Need 3D printer filament? Got milk?

Want to feel better about the environmental impact of all of those bongs and handguns you've been cranking out of your 3D printer? Stop ordering plastic filament in bulk, and dig into your recycling bin full of plastic milk jugs instead.

A study from researchers at the Michigan Technological University makes the case that plastic containers, particularly those made from high-density polyethylene (HDPE), can be home recycled into so-called "3D printer ink," which would transform the recycling industry as we know it.

For starters, it's all about the money. To begin, you'll need to equip your home or neighborhood center with a combination of office shredders and "RecycleBots," which work together to turn your old jugs into filament. That means an up-front cost of hundreds of dollars. But according to the study, those rigs convert milk jugs into filament at a rate of roughly 10 cents per kilogram. For perspective, Amazon's cheapest plastic filament offering currently sells at $31 per kilogram.