when there is fingure print that means the patina
was added, try this
boil hot DW.
add some Backing Soda to the water.
take the water off the stove and put the coin on it and make sure that the backing soda is covering bth sides of the coin.
when the water is warm enough to put your hand in it roub the coin very Gently in both sides and make sure not to scrach it.
run hot water on the coin and leave it under light source.
all the best