Primal ashes are a 100% drop from the strongest demons in RuneScape and can also be obtained from weaker demons such as Abyssal demon, but this is rare. They can be scattered for 480 Prayer experience, taken to the Ectofuntus for 1,920 prayer experience or used at a POH gilded altar with both incense burners lit for 1,680 prayer experience. Note that if you use demon ashes on the Ectofuntus, you do not need to use them on the bone grinder to produce Bonemeal. The Primal ashes give the best prayer xp from all the other ashes (eg. Infernal ashes). But the ashes are untradeable, so they can only be obtained as a drop from monsters.