Help cleaning a pellet mill die

Without giving too much info. I need some input from the internet. Pellet mill die, very very small holes, packed up with rock hard charcoal substrate, super hard because of heat. A 1/4 of the die is still packed and I cannot push them out. Drilling is not an option as it would take too long. Im looking for recommended cleaning agents or caustics to try soaking it in.

Or perhaps, other methods?