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View Full Version : Getting smells of your hand with a metal spoon...I needs the science.


Shirley Ujest
07-05-2004, 10:26 PM
I own an Onion-Off little slab of metal that if I have cut something stinky with my hands, that if I rub it with this slab under cold water, the smell comes off.

This also works with a metal spoon.

I also experimented today by eating a piece of onion and then rubbing the Onion-Off on my tongue and, well, it seemed to take the taste off my tongue where I touched it. The area on the back of my tongue that I could not get the smaller than a credit card metal piece to get too that far back. Sorry, deep throat I am not.


How does this Onion off thingie work?

antechinus
07-05-2004, 11:10 PM
Are you sure this works? It doesn't make sense. Even if the thiols (onion smell) were adsorbed by the metal (thiols - sulphur containing functional groups) there would be a huge number of the molecules still impregnated in the skin.

Onion doesnt have much taste, it has flavour - it smells. The olfactory receptors, which are not on the tongue, sense the 'flavour'. So sticking the metal gizmo on your tounge would only stop your tounge from smelling.

You need to design a more robust experimental protocol. Put onion on all fingers, treat one finger with gizmo and get a friend to smell your fingers. Reverse the procedure with your friend acting this time as the smellee.

ambushed
07-05-2004, 11:11 PM
I own an Onion-Off little slab of metal that if I have cut something stinky with my hands, that if I rub it with this slab under cold water, the smell comes off.

This also works with a metal spoon.

I also experimented today by eating a piece of onion and then rubbing the Onion-Off on my tongue and, well, it seemed to take the taste off my tongue where I touched it. The area on the back of my tongue that I could not get the smaller than a credit card metal piece to get too that far back. Sorry, deep throat I am not.


How does this Onion off thingie work?

This has remained an active question here at the Straight Dope ever since The Master took a hand at trying to answer it 5 years ago and pretty much failed. See: Can stainless steel and running water remove the smell of garlic? (http://www.straightdope.com/classics/a990618b.html) from 18-Jun-1999.

Then check out the following discussion we had shortly after (thread # 139!): Smells and Stainless Steel (http://boards.straightdope.com/sdmb/showthread.php?t=139). I submitted the OP and Xray's first contribution was post #4 (handles have been replaced with the name "Guest" in these old archives).

I wonder if Xray is still around and if she ever completed her experiments?

antechinus
07-05-2004, 11:12 PM
Oops, missed a bit.

Are you sure this works? It doesn't make sense. Even if the thiols (onion smell) were adsorbed by the metal (thiols - sulphur containing functional groups are bound by some metals) there would be a huge number of the molecules still impregnated in the skin.

antechinus
07-05-2004, 11:25 PM
Just read the thread ambushed posted - the whole thing sounds sus IMHO.

Will have to wait for the experimental data to come in.

Squink
07-05-2004, 11:28 PM
Even if the thiols (onion smell) were adsorbed by the metal (thiols - sulphur containing functional groups) there would be a huge number of the molecules still impregnated in the skin.
This bit of tin foilery covers that problem (at least for garlic, and the smelly components in onion are similar):Well Iron ions are pretty good at flipping the spin on oxygen, and thus reducing the activation energy of oxidation reactions. The ion's large, soft electronegativity also catalyzes many free radical based mechanisms.
Allicin, the primary source of garlic odor, is quite unstable chemically, and likely susceptible to degradation by either iron ions in solution, or iron bound as hydroxyls to the surface of the "stainless steel soap." Stainless Steel "Soap"? Huh? (http://boards.straightdope.com/sdmb/showthread.php?t=173472&highlight=steel+garlic)

The iron would be acting as a catalyst, not a reactant.

AskNott
07-06-2004, 12:53 AM
:rolleyes: Oh, sure, but the real trick is taking the garlic smell off your hands, and then sticking the spoon to your nose. :D Buncha pikers. :p

antechinus
07-06-2004, 08:18 AM
btw the smelly principle in onion is a disulfide not a thiol. Thiols contribute to the cooked onion smell.

Still, the disulfide may coordinate to Fe.

I wonder how iron salts would go at getting rid of the smell.

antechinus
07-06-2004, 08:29 AM
This bit of tin foilery covers that problem (at least for garlic, and the smelly components in onion are similar): Stainless Steel "Soap"? Huh? (http://boards.straightdope.com/sdmb/showthread.php?t=173472&highlight=steel+garlic)

The iron would be acting as a catalyst, not a reactant.

Sounds pretty convincing though - at least for allicin.

The alliin is partially oxidised by the iron to the aldehyde, allinaldehyde (or allinalda for short). This tastes great on bangers and MASH. Also the iron can initiate polymerisation of allicin to form short chain polymers, known as allicin chains.

Mangetout
07-06-2004, 08:30 AM
Just read the thread ambushed posted - the whole thing sounds sus IMHO.

Will have to wait for the experimental data to come in.
certainly the OP in that thread made a huge assumption in putting it all down to acclimation and this is easily tested by rubbing both hands with garlic, then rubbing only one of them with the metal - I'm pretty sure (I'll test this myself tonight) that this effect is real and that the smell will be eliminated on the one hand while still very noticeable on the other.

antechinus
07-06-2004, 09:01 AM
Mangetout inspired me to do an experiment too - here is what I just found.

1) Rubbed onion on fingertips of one hand.
2) Waited 2 minutes to absorb odour
3) Rinsed all in cold water
4) Smelled fingers - all smelled
5) Washed 1 with cold water and SS spoon and 3 with cold water and ceramic cup, left one as a blank
6) Smelled fingers - none of washed fingers smelled
7) In order to elliminate olfactory fatigue asked Mrs antechinus to smell my fingers
8) Explained to Mrs antechinius what I was doing
9) Mrs antechinus smelled fingers - could not smell anything

conclusion: for the amount of onion that was impregnated onto fingertips, washing with cold water and any kitchen utensil was sufficient to remove odour.

Further experimentation should be performed with longer period of exposure of fingers to onion (eg make spag bol) prior to washing tests in order to differentiate efficacy of various household items at removing onion odour. Will submit grant application to Mrs antechinus for funding.

clayton_e
07-06-2004, 01:03 PM
I'm confused.. Do you wash your hands with the metal by having the water run over it then onto your hands? Or do you wash your hands while holding and touching the metal to parts of your hands? or what?

Mangetout
07-06-2004, 06:55 PM
You use it like a bar of soap, except it is metal and (relatively) non-soluble