Is There Any DIY Way To Color JBW or Epoxy Black? (Homemade Pigment/Colorant)

[VWFringe]

Any suggestions for changing the cheap yellow epoxy black?

I see epoxy pigment available online for $10 plus shipping, but was hoping crushed up charcoal or something simple might be known

EDIT: I may try mixing in black nail polish (have to buy some).