Related Clues:

• Aquarium buildup
• Lowlifes
• Smelting by-product
• Sediments
• Slimy film
• Smelter waste
• Residue
• Coal furnace waste
• Surface impurities
• Bottom-of-barrel contents
• Remains in the bottle
• Mine waste
• Pond-surface film
• Slimy coating
• Bath water residue