Using Muriatic Acid (found at your local hardware store) and Hydrogen Peroxide (found at your local drug store) Felix Rusu from LowPowerLab was able to make a DIY SMD Metal Stencil using a Pop Can. He cut out a section of the aluminum can wall and transferred the SMD pad image to the metal using the toner transfer method. Touching up some of the imperfect areas of the transfer with a sharpie marker was needed in a few imperfect places. A quick soak in the acid solution ate through the metal in the areas that were not protected by the toner or marker. As you can see the results are quite good. Felix uses an oven to reflow his parts but you could also reflow the SMD parts using a heat gun as Dave recently demonstrated.

Via: Adafruit