Maybe you know about this stuff already, but I only discovered it this week. The notion of a bar of soap that can’t be worn out was intriguing, and when I asked several friends, they didn’t know about it, either. A web search, however, showed about 275,000,000 hits in .6 seconds.

This is not all-purpose soap, of course, but seems to work well. Its use is to remove the odors of onions, garlic, fish, etc. from your hands, which ordinary soap often leaves behind for the first couple of washings. One review even says it works for motor oil, which is reasonable from the science described below, because the oil will contain some sulfurs. I would expect less success with gasoline because most of the sulfur (as I understand it) has been removed. Another manufacturer claims the soap works for smoke and refrigerator odors, which my reading of the science does not support. In any case, you just rub it around under running water, like ordinary soap, and it takes away the odors.

To review the science behind stainless steel soap, you could visit the website of a company called Thoughtco, where it says: “The sulfur from the onion, garlic or fish is attracted to — and binds with — one or more of the metals in stainless steel. Formation of such compounds is what makes stainless steel stainless. Onions and garlic contain amino acid sulfoxides, which form sulfenic acids, which then form a volatile gas — propanethial S-oxide — that forms sulfuric acid upon exposure to water. These compounds are responsible for burning your eyes while cutting onions, and also for their characteristic scent. The sulfur compounds bind to the steel — efficiently removing the odor from your fingers.” More complete information can be found on the website.

If you visit their site, note they suggest wiping your hands on the flat side of a large stainless steel knife. My experience suggests that will work, but is probably not the best way. I noticed when I recently chopped up an onion with some really nice stainless steel knives that I did not suffer from watery eyes while I worked. Then, when I visited the site, they showed a great picture of a guy wiping his finger along the blade with the sharp side pointing inward. He was presumably trying to de-odorize his finger, not cut it off, but I recommend using the stainless steel soap for that instead of following his lead.

I found prices for these bars ranging from about $2 to about $32, with no obvious reason why. One is evidently the size of the bars, a couple have little dishes with them, and another is likely a matter of the actual stainless steel alloy a given manufacturer is using. As is often the case, the term “stainless steel” covers a lot of ground. There are many ways to specify and make it, and I certainly do not speak that language. In the end, I doubt it makes much difference for soap. I chose a larger bar for easier handling and a relatively low-end price.

Sounds like the perfect gift if your sulfenic acids or propanethials are needing a little TLC.

The Recycle Bin is a weekly column on what to recycle, what not to recycle, and why, in Brunswick. The public is encouraged to submit questions by email to brunsrecycleinfo@gmail.com. Harry Hopcroft is a member of the Brunswick Recycling and Sustainability Committee. This column is a product of his own research.