At first glance it looked like a lamination to me but that doesn't explain the rim. It looks like a interesting CUD to me. I can't find anything like it in my limited resources. I will be interested in what the more knowledgeable 2 cent guys 2 cents worth is.
I don't think it's a cud or die crack. Look at the smooth inside rim in that area - notice it doesn't show the denticles, like the rest of the coin. Based on what I can see in the photos, that area was 'hit', and the metal moved to the right, coming off the rim, which is now 'smooth' with the denticles missing.
If I dip the coin in hot water would it take of excess dirt and grime .or is that a bad idea for coins?
No - you can buy Acetone at Home Depot, and with a Q-tip, go over the surfaces of the coin. Most of the black will come of onto the Qtip, but the coin isn't that bad to begin with, so it's really not needed unless you really want to.