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
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.