OK I'm guessing you have all heard about "medical grade" nitrous, and how it is superior to "whippets" or "racing nitrous" and i just want to debunk some myths and provide some harm-reduction info. First off, N2O is N2O no matter what. The purity is what counts. In whippets, some CO2 may be in there which is pretty harmless. In "racing" nitrous there is <100PPM Sulfur Dioxide (rotton egg smell) to deter people from inhaling it. SO2 is acidic. If one were to bubble the contaminated N2O through water made basic (with baking soda) it would remove most of the sulfur, leave the O2, and N2O, and there you have it... "medical" nitrous. Best results I've had were using a "double bubble" system and a pressure regulator. I leave the construction of your filter up to your imagination.
i thought the shit in automotive n20 had another chemical in it that was extremley dangerouse to inhale...justsayn20.com...or justsayn20.org i cant remeber which...
The easiest way is to order nitrous cartridges 8g & 16g and a cracker used for making homemade whipcream. They also sell crackers designed just for recreational use on ebay. Medical grade is pure and I'm sure this has some innert gas like nitrogen in it, but it works.