One Inca tribe used a crazy method of preserving people's heads. This process is called tsantsa and allowed warriors to wear the shrunken head as a symbol of strength. It obviously scared other tribes but the Inca also thought they need to protect themselves from the dead person's evil spirits. The Shuar tribe used this method but it is illegal today.
The process was pretty gruesome. After the victim was dead, he was decapitated which means his head was cut off. Often the killer removed his own headband and looped it through the mouth and neck of his victim to make a hasty or quick retreat.
When time allowed, the skin and hair was carefully peeled from the skull. The skull and brain was thrown into the river as a gift to the anaconda which were giant snakes. The eyes were sewn shut with a vine or string and the lips were closed and skewered with wooden pegs. These were removed later and replaced with dangling strings. Then, the mask went into a sacred boiling pot. The head was simmered for 1 and 1/2 to 2 hours.
After simmering, the skin was dark and rubbery and about 1/3 of the original size. It was then turned inside out and all the leftover skin or meat was scraped off with a knife. The slit or main cut was sewn back together. It now resembled a Halloween mask - only smaller.
The final shrinking was done with hot rocks and sand. The stones were placed inside the "mask" or head and continually rotated so they did not burn a hole in the skin. Eventually, the mask became too small for the stones so hot sand was poured inside to reach small places like the nose, ears, and eyes. The heat from the stones and the sand caused the mask or head to shrink even more and to be tanned or preserved like animal hide.
The shrunken head was then hung over a low fire to harden and blacken some more. Care was taken to make sure it looked life-like so they would add decorations if needed. This whole process took about one week. Finally, the warrior would wear it as a necklace or on his belt. It was a symbol of power, pride, victory, and strength. They also believed it kept them safe from the evil spirit of the person they had killed in battle.