A four hour preparation session reveals a full Asaphus lepidurus.
I knew this one had problems going into it, such as discolouration of the shell, some very sticky calcitic film, and possibly some damage. However, it turned out much better than I anticipated.
I had thought it was likely missing a good chunk of the left side, but I was delightfully incorrect. It is a bit crushed/flattened out on that side, though, but worthy of being put in the display cabinet.
Time lapse GIF above, and a "before and after" picture side by side:
And finally just two pictures detailing how I got into the nooks and crannies. The entire prep involved a range of tools (air scribe, two Dremels, a lot of pin vise work, and Paasche AECR air eraser using dolomite at pressures 20-40 PSI). Believe it not, most of the work was painstakingly done by hand with the pin vise. As the matrix is far too thin on the left side, and the pleural segements stretched out / flattened which makes them a bit more fragile, I'm leaving that side alone.