Excellent product - excellent results
Update June 2021:  I realized that my first review was given after not completely following instructions.  Instructions say to first clean the coin with a mild soap solution.  When doing this I got really excellent results.  It will remove more than surface dirt, although best used on a coin that is in F or better condition.  Changed to a 5 star rating and highly recommend it!  (comment about packaging still applies)<br /><br />This pretty much does what it is advertised to do.  It removes some dirt and tarnish from coins without really doing the type of deep cleaning that would lessen their value.  Be aware that this means it will not remove much more than surface dirt and blemishes and this somewhat weakly.  Don't expect it to change a dark coin to have luster.  It is also pretty pricey.  So if you are an experienced coin collector it is a good thing to have.  If you just want to really deep clean coins and don't care too much about their subsequent valuation by a numismatist, baking soda cleans much better for a lot less money.<br />Beware!  This is a liquid that for some reason was packaged in a jar rather than a bottle.  When I opened it I got spills all over the table it was on.
Rating: 5 stars