The uncharged wicked pouch is an item that can be bought from Solomon's General Store for 20,000 Loyalty Points. The pouch can be charged with any type of (tradeable) rune, and turns the rune into runic energy, which is stored inside the pouch. This process is not reversible, and the item becomes a charged wicked pouch.
After charging it to its full capacity, it is not possible to add more charges to the wicked pouch. When the pouch is completely drained of runic energy, it will turn to dust. Because of this, it can only be used once.
The wicked pouch is always automatically kept on death, even in the Wilderness.
Trivia
It was possible to buy wicked pouches with 80 RuneCoins until an update which made them only obtainable via 20,000 Loyalty Points.