Instructions
Go to the Grand Exchange and purchase pure essence. If your mining skill is level 30 or above, you can mine for pure essence. Buy one binding necklace for every 15 dust runes you want to make.
Fight the level 2 goblins at Lumbridge to obtain an air talisman. Get an earth talisman by killing men, women and farmers. When used together at an alter, these talismans will turn pure essence into dust runes.
Train your runecrafting skill to level 10, which is when you're capable of creating dust runes. Wield a binding necklace.
Head southwest of the Cooking Guild between Lumbridge and the Barbarian Village. With the pure essence, air talisman and earth talisman in your inventory, enter the air alter.
Craft dust runes until you run out of pure essence. Each time you craft 15 dust runes, the binding necklace will turn to dust. If you don't wield the binding necklace, you will only have a 50 percent of successfully creating a dust rune.