All you need is one soda can of your choosing, box cutter/razor blade or anything like that your comfortable with, and some pliers.
Step 2: Getting started
After you have consumed your beverage take your cutting tool and begin to cut out the top of the can, (away from yourself!) Keep on cutting until the top of the can is removed, as in see in picture # 2.
Step 3: Safety First
Now heres where the pliers come in handy. use the pliers to pinch the sharp edge inward, away from the opening. Be careful not to squeeze too hard and ruin the can.
Step 4: Finshed
Now you can put pens, pencils, flowers, soda tabs, anything in it and its a cheap decoration. Be sure to clean out can before you put things in it.