The "milky" appearance is due to the cleaning agents and is probably not specifically listed as to components on the can. Use pure acetone, it will evaporate 100% and not leave residue itself. When acetone evaporates , it carries any moisture from the metal, so I recommend do not rinse in any water afterwards, Jim
Sometimes, stress sometimes, a coin may have a whitish cast to it after having been rinsed in acetone. But there's several different scenarios involved that can cause this - and it can be due to any of them. Sometimes it contaminants that get dissolved in the acetone and remain on the coin when you pull it out. Yeah the acetone evaporates but the contaminants don't and they can cause the whitish cast. Using at least 3 bowls of clean, unused, acetone and rinsing in each will solve this problem. Other times it's because not everything on the coin got removed in the first go round. And yet at other times, there are no contaminants remaining because the coin was rinsed correctly, everything did get removed, and yet the coin still has a whitish cast to it. Typically this happens with silver coins. (but like I said above, this does NOT always happen, only sometimes) So what causes it in this case ? The same thing Jim mentioned above - the acetone removes all moisture. Put some acetone on the skin of your arm, you'll see the skin get a whitish cast to it when the acetone evaporates. This is because the acetone has removed surface moisture and oils from your skin. But wet your finger and rub it over the white spot - and the white spot will disappear and not come back - because moisture has been returned to the skin. Same kind of thing can happen with some coins. But here's the thing. Leave the coin alone for a few days exposed to the air and the whitish cast will disappear. Why ? Because moisture has been returned to the coin from the humidity in the air. Or, give the coin a final rinse in distilled water, and then it dry properly, and it will never have that whitish cast to it. (And yeah, I know your skin and a coin are not the same, I'm merely using it as an illustration because of the similar result.) Some argue against this procedure saying moisture is bad for the coin. But if the coin is dried properly after the final rinse in distilled water then the coin has no more moisture on it than it gets from the air to begin with. So there is absolutely no harm done to the coin from this final rinse in distilled water. Nor is there any additional moisture. The coin will be as dry as it would be normally. Those who argue against this idea then say why do it if it's going to get the moisture from the air anyway eventually ? Well, here's why. Just like nature hates a vacuum, nature also hates desiccation - a total lack of moisture. About the only way I can explain it is that when all moisture is removed it kind of rushes back to the coin - taking any contaminants in the air with it - and they stick to the coin. But if the moisture is already there - it doesn't happen. And since the distilled water is clean there are no contaminants sticking to the coin. And you can seal it up in its holder being as clean as it can get. That's about the best you can hope for.
Interesting analogy, but I'm having trouble working through the details. Acetone turning your skin white makes sense. If the acetone pulls moisture from the skin then it makes sense that the dehydrated skin cells, etc would look different. But how much water is originally adsorbed onto the surface of a coin and how stable is that layer? Is the adsorbed layer even thick enough to change the diffraction of the light? Hopefully the chemists and/or physicists can provide some input
Metal doesn't absorb moisture in the normal sense of the word, and certainly not like skin does. But, all metals definitely have moisture on their surfaces and that moisture absolutely changes the way that metal looks. Put moisture on anything and the way it looks changes. As does anything with a complete lack of moisture. And this is undeniable - by anybody.
Acetone is also a strong fat solvent, so the discoloration in the skin after extended contact is due to that more than water loss. One of the concept of a "Keto" diet ( high in fats and low in carbs food -or- semi-starvation diets) is that natural acetone ( ketosis ) is produced and helps extract extra fats in the person's storage. research has shown some benefits from the low frequency of feeding ( you can only eat during set time of day ( such as 3 hrs) and can have high fat during that time. Most people like the high fat food idea, but not the feeding time ( similar to wandering paleolithic humans). Miss your feed time, is like missing the rabbit that day
Actually, acetone is produced from the degradation of fat (tryglycerides) in adipose cells; it doesn't extract fat from the cells. Short version is that hormonal changes associated with low blood sugar (because of low carb diet and a while since eating) cause lipolysis (fat dissolution) in adipose cells. The fat is released into blood in the form of long chain fatty acids. The fatty acids can be burned in metabolism (mostly by muscle). However, if more is released from adipose than can be burned, the liver takes up the excess. The liver may convert some back to fat, causing fatty liver, and it converts some to the ketone bodies, betahydroxybutyrate and acetoacetate, which are released into blood. Acetoacetate is inherently unstable, and a portion of it spontaneously decomposes to acetone and bicarbonate. Acetone is effectively a metabolic dead-end and is lost from the body in breath and urine. Blood acetone that is produced from metabolism of fat is far too dilute to act as a fat solvent. However, applying relatively pure acetone to coins or skin will certainly de-fat them. Cal
