It depends on the bundles! Virgin bundles that come in the color Natural Black have not been pre-colored, so they are ok to be dyed or lifted. Our #27 Dark Blonde and #613 Blonde bundles can be colored with deposit-only color or toner, but shouldn't be bleached any further. Our pre-dyed bundles that come in colors #1 Jet Black, #2 Chocolate Brown, #4 Caramel Brown, and Vibrant Burgundy shouldn't be processed any further.