Sometimes you need to make small holes in plastic items, and don't have suitable instruments like a thin enough drill bit. Then this method using a soldering gun could come in handy.
1. Your favourite soldering gun/iron.
2. A piece of wire with the diameter of the size of the hole you want to make.
Step 1: Prepare the Wire
We're going to attach a piece of wire to the tip of the soldering gun/iron to act as a smaller, secondary tip. Snip off a piece of wire slightly longer than you think you will need, and bend it with a pair of pliers to ready it for fixing it to the soldering tip.
Step 2: Fix the Wire to the Tip
Fix the wire to the tip of the soldering gun/iron, with a piece sticking out in front forming the secondary soldering tip. Use the pliers if necessary to make sure the contact between the wire and the soldering tip is good, otherwise the heat conduction will be poor. Cut the protruding wire tip to the shortest length you need, which will provide the most heat.
Step 3: Make the Hole
Heat up your soldering gun/iron, and melt the hole(s) in the plastic. The shorter the wire tip, the more efficient this method will be.
Step 4: Admire You Work!
Sorry if this instructable was a bit long winded, but it was my first try at writing one.