I threw out all my driers back in the 90's knowing that they were all very toxic: copal medium, cobalt drier, and Japan drier. So nowadays, I speed up the drying time on my paintings by heat only, and of course time. As you know, oil paintings do not dry by evaporation of water but rather oxygenation of the oil and pigments. After some research the only methods that would speed up the oils to a degree of solid form is to add heat and alcohol. So after I am done with a painting and need for it to dry quickly, I will spray a little alcohol and sit it in front of a heater. Titanium white and all cadmiums takes the longest to dry and surprisingly Yellow Ochre too! The reason for the rush is that I still do a glazing process after the painting is dried to the touch.
If anyone knows a better method, I'd love to know!