How can you tell if a coin is improperly cleaned?

I had 10 coins that I had submitted for grading, and had my coins looked over thoroughly, and had 4 out of the 10 come back with improper cleaning. (I didn't clean them, I bought them because they were in great shape and the price was right.) The price matched what was right with NGC, so I had them checked and sent them in.

The 10 coins I sent in for my first submission were an 1806 Bust half (Which came back as VG8), an 1817, 1818, and a 1830 Capped bust (Whic are coming back IMPROPERLY CLEANED, with VF DETAILS) , a 1941 (Which came back as a MS 63, I was figuring at leat a MS 65 to MS 66.) and 1946 (Which came back as a MS 61, and I was figuring at least a MS 65 to MS 66.) Walking Liberty halves, a 1941 (Which came back as a MS 64, and I was figuring a MS 67 or MS 68, it has high definition and no nicks, and follow what the books tell you to look for.) and 1946 (Which cam back as a MS 64 , I was figuring it as a MS 66 or MS 67, again the details were all there for it according to the books.) Washington quarters, a 1941 Mercury dime (Which cam back as UNC DETAILS, IMPROPERLY CLEANED, again how can one tell when purchasing if it is improperly cleaned, I didn't wee anything different from one to another.), and a 1946 Roosevelt dime (Which came back as a MS 65, and I was figuring it as a MS 67 or MS 68 per the book reference.).

I had figured the insurance purposes around $6400, but as I looked at other auctions for similar coins with the same details that these coins show, I thought I had low balled that. (I was hoping any way.)

What did I learn, that I am not a good judge for coins, and that I wasted way too much money on this. I feel like I was lead astray and am ready to give this expensive hobby up!

To see old comments for this Journal entry, click here. New comments can be added below.