Related Clues:

• Compost collection
• Worst of the population
• Fish tank buildup
• Growth on some ponds
• Compost heap detritus
• Not a nice film?
• It may be radioactive
• Tub buildup
• Ugly pond film
• Toxic ___
• Surface gunk
• Film you don't want to see
• Aquarium concern
• Despicable people
• Not be economical