Most printing inks are make of finely divided suspended solids. Carbon black is not uncommon. Some iron compounds are also used. There are many other formulations.
Depending on many things (exact formulation, quantity, whether water based, to name a few), my first attempt would be by filtering. Other approaches would be boiling, coagulation via addition of flocculants, and coagulation via change of pH.
Rots of ruck.