Firstly, comparing the two coins is irrelevant because what was needed was a before and after picture, no two coins being the same.
 
	That said, it is not necessary to try to use acetone on every coin as the only reason would be to remove soluble deposits, most of which are likely to be residue from fingers. Coins will tone naturally from exposure to the atmosphere. This would not be removed. Some people are obsessed with cleaning everything in acetone - I am not convinced. If it isn't obvious why you would need to use a solvent, then why do it?