Since white spots occur as a result of the cleaning process, in your opinion should it be changed - i.e. switch or omit whatever chemical is causing the problem? The trade off would be (less shiny coin?) greater chance of toning/tarnish. Just curious.
Honestly, I don't collect numismatic coins, so what I say here isn't from first hand experience. I do collect bullion coins though. In the case of numismatics, my understanding is that any sort of washing or cleaning in a non professional manner is highly frowned upon, as, if it's not done correctly, it would potentially ruin the value of the coin in question. If these are bullion coins, on the other hand, I wouldn't bother washing or cleaning them in any way. Some toning on certain products (eg. Perth Mint bars) is quite acceptable, and purchasers of these goods are buying them for the 10oz of silver, and generally don't care if there's any toning involved. On the above basis, I've never cleaned a bar or a coin, so with many apologies, I'd have to say I can't answer your question directly, other than to question what it is you're looking to achieve in your cleaning operation to begin with?
Apologies, should have been more clear. I meant the cleaning process that takes place at the mint itself.
I think something should definitely be done about it. Sure they might be happy with the current volume they are selling, but there is no doubt many a collector or stacker has avoided coins such as the maple due to milk spots. Surely if one major mint can make near spot free coins, another major mint would be able to as well?
Those aggravating milk spots drove me away from the CSM's. I started out stacking those things, but pretty quickly gave up on them. Some time ago, I saw a press release from the RCM in response to public complaints about the milk spots. The essence of what they said was "Yeah--we know, so what's your point?" The RCM is happy putting out the CSM as a low-premium bullion coin and their signature milk spots are of no concern to them. Too bad for the rest of us It's a shame that the RCM's concept of customer relations is "Our ideas good---your ideas bad" but that's the way it is.