Colorants should not affect the plastic in the amounts we use unless something is in the colorant itself. I have many of the X2 colors and even some of the old Caney Creek colors yet along with 40 or so MF colors. I use the MF stuff to adjust colors and hardly ever use the MF stuff stand alone except a couple of the changeable color so I can't really say if I've seen anything there. I do have or use spike it stuff at all.