Reverse electro-plating byproducts
The yellow colour in solution is likely from iron ions from the metal being oxidized and dissolved: 
$$\ce{Fe_{(s)} + 2e- -&gt; Fe^{2+}_{(aq)}}$$ (Probably $\ce{Fe^3+}$, too)

The gas bubbles/smoke is the product of the other half of the reaction, the reduction of something in your solution. Because you have chloride in solution, chlorine gas is a possibility:
$$\ce{2Cl^{-}_{(aq)} -&gt; Cl_{2(g)} + 2e-}$$

Hydrogen may also be produced depending on what you're using as an electrode on the q-tip.