Methods of processing substrates having metal layers are provided herein. In some embodiments, a method of processing a substrate comprising a metal layer having a patterned mask layer disposed above the metal layer, the method may include etching the metal layer through the patterned mask layer; and removing the patterned mask layer using a first plasma formed from a first process gas comprising oxygen (O2) and a carbohydrate. In some embodiments, a two step method with an additional second process gas comprising chlorine (Cl2) or a sulfur (S) containing gas, may provide an efficient way to remove patterned mask residue.