*If you blow your nose after dyeing and the tissue turns blue, you didn't handle the powdered dye safely.
*If you leave a crockpot full of dye on the low setting overnight, you will wake to the aroma of hot, moist burning hair. It lasts and last. It will also turn your roving into slime--hot, smelly slime. Plus I'm pretty sure it's a fire hazard, so don't tell the Housing Office.
*When the color says "hot," as in "hot fushia," it means eye-searing, nosebleed-inducing, potentially visually poisonous. You can make wool look like acrylic if you try hard enough!
*A Mr. Clean Magic Eraser will remove dye from cabinets, counters, sinks, and floors.
*Yellow dye makes your fingernails look diseased. Wear gloves.
*Acid dyes will not dye cotton, but they will stain it. Badly.
*Three days of dyeing probably gets enough chemicals in your household air to negate all of those organic vegetables.