I had this happen once! Our female Schnauzer got RF pigment stick on her whiskers (Green Earth!) and I used regular cooking oil to rub it out. I would recommend using cooking oil rather than any solvents or citrus oil (which is even more caustic than a solvent such as Gamsol!). Pets will lick whatever you rub them with - so I think cooking oil is the best option.  Afterwards, perhaps a bath!