i dont see that tool where is it at?open the image in PS and using the magic wand tool ...select the color you want to change ..this will select all the black or all the yellow...now so you dont ruin the original....create a new layer and fill the new layer with the new color..... then repeat for the other color...
I am not sure..but I just google'd and I found a helpful article
Adobe® Photoshop® CS5 Classroom in a Book: Using the Magic Wand Tool > Using the Magic Wand tool
whats up butcher 909 the way i do it is get the magic eraeser and unclick anti alias and unclick contigious and it will completley take all color off of whatever you click. I was born and raised in pomona where you at. what kinda printing you doing??