Pit Firing is the oldest known method for firing pottery. The unfired pots are placed in a pit in the ground and then covered with combustible materials such as wood shavings, leaves, sawdust, and dried manure. The top of the pit is then protected and covered while underneath is set on fire and carefully tended.
A foil saggar is when the pot is coated with Ferric Chloride then wrapped in aluminum foil which isolates the pottery while it is fired. The foil gets vaporized in the process of firing.
A paper saggar is also when the pottery is coated with Ferric Chloride. Then it is placed inside a paper bag with straw and colorants. The bag will be crumpled and wrapped in layers of newspaper, then fired.