After the colors are mixed, use a paintbrush to paint the dye onto the cardboard tube.
Make sure to use a new, clean paintbrush. Brushes that have been used before can harbor remnants of potentially toxic paints, which could make your bird sick if he ingests them.
Use a basting motion to transfer the dye to the tube, and be sure to completely saturate the cardboard with color to get a bright result once it is dry.
Don't worry if the colors mix or run together. This can create a neat tie-dyed effect that many birds enjoy!

