For those who use Nitrous recreationally, its extremely important to pay attention to the quality and purity of the gas used. For kitchen use in making whipcream, small amounts of residues are probably less acutely dangerous, but are distasteful and are unlikely to be healthy.

Not all nitrous 'whippet' chargers are the same quality. Some whippet brands contain oily grey residues which are likely very bad to inhale. Some of the types of industrial nitrous contain other residue gasses which are highly toxic to inhale (some contain chlorine which is very poisonous).

Brands

• ISI
  • ISI Brand whippets are considered the best quality nitrous for both making whipcream and for recreational use. Many consider them the only acceptable brand for inhaling. ISI chargers leave an oily black residue on crackers, balloons, and whip-cream canisters which is noticeable after a dozen or so. This image depicts the contaminant left after we ran 12 cartridges through a whip-cream maker and then dragged a finger along the inner surface of the cylinder.
  
  
• EZ-Whip
  • EZ-Whip brand whippets are reported to contain oily resides. Although they are generally cheaper than ISI, this report states "[do] NOT buy regardless of the purpose." Other users report that these chargers add a 'bad' taste and cause headaches. These chargers are metallic with some black printing on each.
  • Another Report about EZ-Whip brand: "Being a bargain hunter at heart, I switched from ISI brand to EZ Whips. After an evening during which three people consumed the contents of nearly fifty EZ Whip chargers, the cannister was placed back on the shelf, until three days ago, when I decided to make whipped cream again. I opened the cannister, and immediately noticed a greyish residue on the inside of the cannister and inside the lid. Wiping it off with my fingers, I determined it was a grey, oily substance, not unlike machine oil." - MC
  
  
• Leland Gas Tech
  • One user reports these are without oily residue.