Southern CA has possibly the worst tap water in the USA...exactly what does this mean? When I lived in San Diego, I analyzed the water and found it to be about 800 ppm dissolved solids, the government sets 250 or so as the top safe limit. Now what does 800 ppm mean? To get to percent (which EVERYONE understands) divide by 10,000 and get 0.08 % meaning that water was only 99.92 percent pure, and this is one of the worst cases in the US. Now don't get me wrong, I don't like 0.08% and that is why I dry the water off by blotting with a soft towel (don't rub). A nice distilled water final rinse is a good thing too.
These are possibly the best for us beginners; but there are many, many, many more. You need proper ventilation and disposal (even for acetone). Perhaps a professional conservation expert can reveal some of the chemicals they use; but then they should need to kill us...LOL
Yup...and the more experience they have the better. I'll bet Brian Silliman covers this topic at his ANA sponsored seminars.
To sum up what I think I have read here: A. Cleaning a coin is a difficult undertaking to be tried only by those who know what they are doing. B. A lot of us should not even think of trying it. I fit category B.
Cleaning a coin is easy. Anyone can do it. However, you'll need an experienced, competent, teacher to learn how to do it "right" (most of the time). Even the experts have had coins "blow-up on them when everything pointed to an easy & quick job. The guys at NCS sign a confidentially statement and cannot reveal the chemicals or methods they use. Nevertheless, things like acetone, deionized water, dip, etc. are commonly employed by conservators. Believe it or not, it's a good bet that many dealers/collectors like many here have taught themselves over the years w/trial & error to do excellent work. Key is to know what you are doing to increase the % of undetectable, satisfactory outcome. That's why everyone of us WHO CLEAN COINS ON A REGULAR BASIS tell others not to clean their coins.