Black organic cotton long-sleeved 'clean up or die' T-shirt from Katharine Hamnett London featuring a crew neck, long sleeves, a relaxed fit, a skull print and a straight hem. POSITIVELY CONSCIOUS: Katharine Hamnett scores 4 out 5 by independent ethical brand rating agency Good On You. It uses some eco-friendly materials and low impact non-toxic dyes in all of its products. It manufactures locally to reduce its carbon footprint and does not use fur, leather or exotic animal skin.