I heard from a friend of mine that when I get gray hairs when I'm older, I won't need to bleach my hair any more to use the Manic Panic/Special Effects/etc. colors xD

Though it seems kinda silly, I was intrigued.

Do these colors show up well over natrually gray hair?

Specifically the warmer colors, like red, or orange. I tend to use those colors more often.

And yes, I do plan to dye my hair when I get that old :]

thanks.

Well, I still think you'd need to lightly bleach the grey hair. Grey hair tends to be more resistant to coloring in general, and healthy hair that's not color treated tends to not be as porous. I think that the reds/darker colors would work well and give a vibrant result if the hair was WHITE, but on grey hair, you'd still want to lift some color. Plus, most people with grey hair have subtle variations on the color (just as we all do). It'd probably work best if the hair was "evened out" a bit in color.

They definitely won't cover grey without some kind of pre-treatment.