In general - with many exceptions - unpolished/uncleaned proofs are characterized by sharp, full strikes, very smooth fields which often appear mirrored, and lots of original luster. Again, in general - with some exceptions - polished coins lack luster and are covered with fine hairlines which are usually visible to the naked eye and almost always visible under magnification as low as 3x. That said, the most precise answer to your question is one word: Experience!
All very true. Right on, H. Polished coins look awful, and are conspicuous out the corner of one's eye. Polish marks / lines are unmistakable under low magnification, as stated above.
It's also difficult to polish around letters, numbers, stars and any other tight spots witout it being obvious. Bruce
See this thread here - blow up the picture on the obverse. You can see the hairlines and the areas around the stars. This is what typically happens to a coin when polished. Yes - the coin in the picture is harshly polished, but I still like it. So this is an example of polished - now go look at some xf/au graded coins and you will see how obvious the polishing is.
