Darkoshi

Why can we smell metal? - it's not actually the metal that smells.

I was wondering last week why my hand smelled bad, then realized it was from simply having touched the metal zipper pull on an old duffle bag. (Yet when I later sniffed the zipper, it didn't smell). Certain metals like that (not sure what kind, but generally the yellowish/bronze colored ones) make my hands smell so horrible that I have to wash them to get rid of the smell. Then I wondered if other people could smell metal too, which led to me finding the above information.

Propanediol versus Propylene Glycol - explains the difference.

Some years ago when several deodorants started listing propanediol in their ingredient list, I looked up what it was. Based on the info I found, I thought it was just another name for propylene glycol.

Seeing as some personal care products stated on the label that they were propylene-glycol-free, yet they had propanediol in the ingredient list, that seemed deceptive to me. Or as some kind of marketing ploy - apparently some people are allergic or sensitive to propylene glycol, or dislike it for other reasons. I've never noticed any problems with it, personally.

But the document at the above link explains that both compounds really are very different, even though they have the same formula, C3H8O2.