As far as I am concerned, the chocolate will best be used for eating.Wwhile many people have heard of this fad in recent years, most of them have been disappointed if ever they have tried it. But yes, the parabolic surface of the bottom of a beverage can can be used to make fire. Not so hard, if you know the real scoop about how.
You may have heard of this. Better try it first. I am only guessing that whomever has posted videos or instructions about this is either showing their disappointment with proof about how it does not work, OR, has fudged the results by leaving out some important information. It can indeed be done, but perhaps not as easily as some folks may let on. I have known about this method for a very long time. The bottom of a pop can or beer can, is after all a parabola, albeit a shallow one. Many of the same reasons and mathematics that enable a parabolic reflector work to start fires also make the can more structurally sound.
Almost without exception, chocolate and or toothpaste are also part of the oft-cited equation for making the can shiny enough to work as a reflector for fire-making. I am not sure who started this notion. If I did, I would happily credit them. However, I don’t really think either chocolate or toothpaste or both work very well, if at all. Sometimes the bottom of the can is shiny enough without any additional polishing–if several other conditions are just right. These other conditions are most likely more important than the chocolate or toothpaste.
I am no expert on polishing stuff, but I do have some pertinent experience. As do others who have ever gone through military boot-camp, I learned how to spit-shine leather shoes to a mirror surface.
The salient steps to polishing already smooth shiny surfaces involve progressing through finer and finer grades of grit with and/or without lubricant until the desired shine is accomplished. Once the limits of one medium is reached, you can polish forever without making much additional gains in shine.
Just for grins, I have given both toothpaste and chocolate more than a sufficient test to convince myself that neither nor both helped much–without supreme effort, luck, and some dead-end disappointment. The mere friction will rub the usual inked imprints off, but this is not even required to make the pop can reflector work if the other conditions are met. In fact I got better results in half an hour using nothing but moisture (spit and breath fog) and a piece of soft cotton flannel shirt than I did in over and hour using chocolate and or toothpaste. Further, you are likely spinning your wheels unless you have char cloth or other really low-ignition temperature tinder to light.
fortunately, there are other good alternatives for polishing a can you can read about at the my broader blog link below as well as future links herein as I have opportunity to post them.
You can learn more regarding how to do this at my blog post from One Hundred Ways to Make Fire without Matches. Fire from a Beverage Can