I found these old pics in my camera and I realize that I had never posted any of them.
What you need:
Pin ( the ones that come with dress shirts and the smaller the better)
Drill bit of the same size of the pin.
Spilled toner or a ground up pencil lead.
We use laser printers at work so we are always cleaning them up. We use these cotton pads, but a cotton ball will work better.
Drill into the exhaust. I use a hand drill with a dremil bit on it. (sorry, I did not take pics of that).
Roll the cotton on the toner or pencil lead making sure you do not get too much.
Tear a small part and stab the pin through it and then put it into the exhaust.
After you have it in place, pull and shape the smoke into shape.