Possible Clues:

• Dye used as a toner
• In Berlin, one secures rating for red dye
• Rose-red substance
• Gasoline colorant
• Red stain in a lab
• Acid dye
• A German one accepts special order in return for dye
• Dye manufactured from 6
• Heartless pride and greed perhaps creating stain
• Helps one see red perhaps in secret wartime military organisation returning in the end