Self-made fuel systems?

I know some of you watch Roadkill on Motor Trend and have probably seen the episode when they recycle pigpen from the junk yard, well I was just wondering how they made their own fuel system out of a normal plastic gas can and if anyone can give me a run down of how this works/ how they do it. or if you could point me to an article somewhere about this. Thank You! via /r/cars http://ift.tt/2sKmuY7