Building an electrolysis unit can be as simple or as complex as you want it to be. 
We will be looking at the construction of two different zappers.  The first and
simplest type consists of parts that you may have at home right now.

Lets build the simple zapper first.

You will need the following materials to make the zapper, the materials don't need to
be an exact match, you can substitute materials if they are close.

-A small plastic container like a tupperware dish.
-A spoon from the cutlery drawer. Be warned the spoon will be   destroyed.                              
-An ac/dc converter. 6-12 Volts and 250-500 mili-Amps would work great.                                
-A couple of alligator clips or small jumper wires. (I have been told solid
copper clips are the best, but I get good results with plated clips)
-A role of electrical tape

1. Using two pair of pliers or a vice and pliers, bend your spoon
 into a shape like this.  This will be your anode, or positive.

2. Next cut the end of the adapter off and separate the wires.

3. Strip about 1/2 inch of insulation off each wire.  On this adapter  one of the wires was entirely bare copper, I just put a wrap of   electrical tape around it

4. Add water to your bowl and put in some salt or baking soda.

5. Place the two leads that you stripped into the electrolyte,
make sure the leads are not touching each other.                                                           

6. Plug the adapter into the wall outlet. Watch the leads in the water,
one of them will start to fizz and bubble, this is the negative lead.  The
negative lead is the one that will go to the coin.

7. Remembering which one of the leads was fizzing, unplug the
adapter from the wall.  Using a piece of electrical tape mark the
negative lead by  wrapping a piece of tape around the wire.

8. Attach the alligator clips to the bare copper ends, this can be done
by crimping or soldering.  I just use electrical jumpers and tape them on.

9. You are done.  Place the bent spoon over the edge of the bowl and
clip the positive lead to it.  Place the coin to be zapped in the negative
clip and put the coin in the electrolyte.

10. Plug in the adapter and watch the crud fall off.  Notice how dirty
the water is after only 5 minutes.


This is the tip of the spoon after zapping just one coin!  You might want to consider some other piece of metal for your anode.  
Here is the result of the zapping, a rather poor As of Augustus (I think)
Want to check out a larger zapper?