@Andres2 what is this magic soup you speak of? I've got 2 of her kids that need some soup too! Hungry for soup on both sides: Not quite as hungry as older brother, but still snacky:
In this case I used Antikal liquid gel , blue color, the stuff to clean chrome taps in bathrooms, 2/3 Antikal 1/3 tapwater. soak it for 24 hours, in between (after a couple of hours) scrap off the mineral stuff with a toothpick as much as you can. should work fine on the second coin PONT I COS II. I wouldn't clean the first coin VICT PART though, I would leave it as it is. The black stuff highlights the details and the legends. If you clean that coin, you end up with lifeless flat coin. I had a similar coin with that sludge from Julia Mammae , that was a hell of a job to clean it. The end result was OK, but it was a high condition coin to begin with. And remember to stop cleaning in time, dont over do it.