Sanitize your work area and all supplies thoroughly. Soak the plastic bottle and lid in boiling water. Wipe down the stir stick and your work counter with a small amount of rubbing alcohol. Run the flame of the lighter over the razor blade several times, and wear latex gloves when performing all of these procedures.
Remove the carbon stick from the pencil by scraping away the wood part of the pencil with the razor blade. Start at the tip of the pencil and work your way down. You do not need a very large piece of carbon, so it is not necessary to strip all of the pencil. Move the blade at an angle, always working away from you so that you do not cut yourself.
Use the razor blade to process the carbon stick into a fine powder. Scrape at the carbon stick with the blade while holding the stick over a piece of paper. Again, always be sure to use movements going away from your body so you do not cut yourself.
Combine the carbon particles, a drop of water and two drops of the shampoo in the plastic bottle. Use the stir stick to mix, and then put the lid on the bottle and shake well. The shampoo contains alcohol and propylene glycol, which not only adds texture to the ink but also helps to sanitize the mixture.
Check the consistency of your homemade tattoo ink. The mixture should not be so think that you cannot easily pour it from the bottle, but it should not appear to be too watered down either. To thicken the mixture, add more carbon particles from the carbon stick. If your mixture appears too thick, add another drop of water.