You will need: Safety matches (with matchbox), sanding paper, a small container, something to stir with, a pair of pliers, a tube or a D-cell battery, and water.
You will also need something to lay the matches on, like a the edge of a table or this CD case that I used.
Step 1: Sanding of phosphorus
Sand off the phosphorus on the sides of the matchbox (striking surfaces) and put the powder in the container.
Step 2: Put on the phosphorus
Put a few drops if water in the container and stir well. Take the matches, one by one, and dip them in the mixture. Then lay them on the edge of the table/CD case.
Step 3: Cover the phosphorus
When they're dry, take some new matches and squeeze off the heads with the pliers, then pulverize the powder with the pipe or battery by pressing it down and rolling it over the powder and then put it in the container (if you're using the same container, be sure to wash out the leftover phosphorus). Add a few drops of water and stir well. Then dip the matches in the new mix so that you cover the phosphorus already on them and let them to dry again for a while.
Step 5: Warning
Please be sure to wash your hands after making these matches, phosphorus is toxic.