The Sacrifice of the Vaal content update for Path of Exile introduced a new currency item to the game: Vaal Orbs. These new orbs can be used on Path of Exile items to corrupt them. Doing so is risky gamble that can get you powerful items, or have you lose an expensive item.
Vaal Orb effects on Path of Exile items
When a Vaal Orb is used on an item is similar to using an orb that rerolls modifiers, except corrupting an item rerolls more than just the modifiers. When Path of Exile items are corrupted, there can be varied results. The best one can hope for are white sockets that can only be obtained this way. Other exclusive alterations include, specific implicit modifiers, 20+ skill gem levels/quality, and eight mod-maps.
Risks of corrupting Path of Exile items
Once an item has been corrupted, currency items can no longer be used on it. Even an Eternal Orb will not be able to restore it to a previous state. Additionally, Path of Exile items that are corrupted can end up weaker as the Vaal Orb can also modify rarity. Make sure the item you are corrupting is something you don’t mind nerfing. Good luck!