It is why you want to concentrate on destroying Monster
This means that players from more advanced levels are able to Buy RuneScape Gold attack you. It's best to put them in the bank and then do the Altar running once you've got enough of the bones stored However, it's up to you to decide whether to take on the risk of putting your equipment in danger.
The other option of training is to train through the Slayer. During your Slayer tasks, you will collect many Insouled Monster Heads, which can be reanimated at the Dark Altar. Killing reanimated monsters gives large amounts of Prayer experience however it's a less consistent method than regular bones farming, and you cannot count on getting enough Ensouled Heads to make it up to levels 1 to 99.
It requires a lot of Pure Essence for leveling purposes and this is earned by mining and monster drops. This is the first way to go but it's not as effective since you'd have spent all day mining stones that do not give you any Mining experience.
It is why you want to concentrate on destroying Monster. Monster not just can drop Essence in large quantities but also other valuable items that can be useful to you. The best options are Gargoyles and Skeletal Wyverns on Slayer tasks. The higher level players can also farm Zulrah boss for drops in the final game and large amounts in Pure Essence.
These are not the only ways to obtain Runes because you can make use of RS 3 Gold other options and benefit from them. Temple Trekking minigame offers a significant quantity of Essences with a little effort, and through finishing Ardougne Diary, you might get daily runes from Wizard Cromperty.