How to make saltpeter, is used where?

Do I need to make fireworks for the saltpetre trade of manure and click when completed collectionu create one. Let us explain where the materials were found; 

• Puddler Poultry, geese and chickens while feeding off of.
• Piggy Poop, while feeding the pigs out
• Brownie brush, goat and sheep while feeding off
• Pile Prairie, is one the most difficult moment while feeding horses and donkeys, horses and donkeys were removed from the general growing interest in the adult in you or your neighbors can be obtained by feeding the horse and donkey, or you can ask your friends
• Meadow Muffin, while out feeding cows and oxen