A method of forming a semiconductor device may include forming a metal layer on a silicon portion of a substrate, and reacting the metal layer with the silicon portion to form a metal silicide. After reacting the metal layer, unreacted residue of the metal layer may be removed using an electrolyzed sulfuric acid solution. More particularly, a volume of sulfuric acid in the electrolyzed sulfuric acid solution may be in the range of about 70% to about 95% of the total volume of the electrolyzed sulfuric acid solution, a concentration of oxidant in the electrolyzed acid solution may be in the range of about 7 g/L to about 25 g/L, and a temperature of the electrolyzed sulfuric acid solution may be in the range of about 130 degrees C. to about 180 degrees C.