The main problem with these coins is that the
red crud isnt simply "on" the
flan...quite the opposite, they are by and large "in" the
flan, meaning that if you delete the boils you now have divots in your coin. Imagine pulling out a tree stump...
The pic below is a nab I took too far...it is hard to tell from the scan, but the divot is about a mm below the actual
flan and just keeps going. This started off as a
red boil about a mm and a half high...
Chris