I've heard touching stainless steel after chopping and handling garlic helps but I haven't found it to work all that well.
The smell of garlic is due to sulfur compounds. When you rub your hands against stainless steel, the iron of the stainless steel will react with some small volume of those compounds, but much more will remain in your hands. Rubbing your hands against an iron object does not work.
The sulfur smell compounds are water soluble to slightly water soluble, so rinsing your hands in cold water and then soap and water should work as well as the recipes suggesting Noxzema, lemon juice, salt, baking soda, raw potatoes, tomato paste solutions, or mouthwash.
I always use a stainless steel 'hand soap', such as this one with a little bit of regular hand soap. Wash for about 30 seconds and the garlic smell's gone.
I was recently reading up on this subject because, not matter how many times I washed my hands after chopping garlic, the smell would still be there even a couple days later.
I tried the "stainless steel" approach, but didn't see any results. The "coffee grounds" approach did help some, it works well to cover up the smell at least. At the same time I was trying these methods, I accidentally discovered a better solution. I was building an evaporative fan, using copper tubing and in handling it, the garlic smell instantly went away and my fingers and slightly smelled like copper but no garlic!!
I imagine this has something to do with the chemical reaction with stainless steel mentioned in this string, but copper seemed to work a lot better. Further testing may be needed, but wanted to share what I had found.