Button-down shirts are great and versatile. However, if you are not wearing a tie and there are no buttons on the collars, you can often look like you are going to fly away with airplane wings around your neck.
This is a simple, inexpensive and quick way to use magnets to create collar stays that will keep the collars on your shirt from looking like you are "cleared for take-off".
There are some folks selling magnetic collar stays for a small fortune ( http://www.wurkinstiffs.com/power-stays/6-2-5-power-stays.html ). You can achieve the same objective with stuff lying around the house for free. I did.
Step 1: The Supplies
Begin with a pair of metal snips, a piece of feromagnetic metal, two small disc magnets, your original plastic collar stays and a marker. If you don't own metal snips, you can probably use good scissors. A rotary tool like a Dremel with a cut-off wheel, or even a saw would likely work too.
I did not buy anything. I took two disc magnets from the back of some old refrigerator magnets. The piece of metal was in a box of junk in the garage. Thin steel or other feromagnetic sheet metal is widely salvageable from old toasters and other items that are commonly thrown away. You can also buy a small metal sheet at hardware stores, craft stores or on ebay. At Home Depot, just walk down the galvanized vent aisle. You will find something cheap that will likely be large enough for collar stays for the whole neighborhood. If you do not have neodymium magnets lying around, these are cheap and widely available at hardware stores, ebay and other sites. You only need two. I quickly found a set of 20, 8mm disc magnets for $3.49 on http://accstation.com/mothremgnt01.html
Step 2: Trace Your Collar Stays on the Metal
Take your original plastic collar stays and trace them on the metal.
Step 3: Cut Out the Metal Stays
I used tin snips to cut out the traced collar stays. You probably could use a Dremel, saw or maybe even some industrial scissors depending on how thick your metal is. The metal I used was easily bendable by hand.
Step 4: Sand Down Rough Edges and You Are Finished
I used a belt sander to quickly sand down the rough edges on the collar stays. You could use a metal file or sandpaper just as well. This step is optional. It does not matter what the stays or the disc magnets look like. They will not be visable.
Step 5: Apply the Collar Stays and Magnets
Put the newly cut out metal collar stays in the shirt. Place the small disc magnets on the inside of the shirt by the tips of the collar. The magnets will easily stay attached to the shirt. I have not had any come off from normal activity yet. You are finished. No more airplane wings. Just remember to remove the magnets and the stays prior to washing the shirt. If feromagnetic metal is in prolonged contact with water, a rusty mess would likely be left on your shirt.