In Diablo 3 for the PC, you can salvage weapons and armor to get raw materials you’ll need for blacksmithing new items. You can salvage magic, rare, set, and legendary items, but you can’t salvage white or low quality items.
To salvage, you just need to bring your items to the blacksmith. You’ll see a tab at the bottom for salvaging. On the salvaging tab, click the salvage icon and your cursor will turn into salvage icon to click on items to salvage them. This makes salvaging extremely fast and easy.
For a while in the beta they made it possible to salvage in the field using the Nephalem Cube, but it was removed later in the beta.