The ink of choice is waterproof black ink but it’s rarely available and very expensive. Convicts invent a myriad of concoctions - scrapings from soft pastels, charcoal pencils, and carbon paper - the ash of burned books, lightweight paper preferred. The flying soot lands on a shiny magazine cover, is scraped off, and mixed with toothpaste and water. Green ink is produced from green toothpaste ("Crest is best") or Prell shampoo - blue from Head and Shoulders or Selsen Blue - red from Robitussen cough syrup.
