If you have a pair of pinking shears, chances are good you've had them for years, since they are such an expensive item for your craft supplies. And when they have gone dull, you have probably discovered that having pinking shears professionally sharpened is extremely expensive.
Fortunately, there is a super easy way to sharpen pinking shears at home. Simply fold a square of tin foil multiple times (at least 4-5 times). Then simply cut the tin foil, making sure that the tin foil is coming in contact with all of the "teeth" of the pinking scissors.
Once done, cut a scrap piece of fabric to see if they are sharpened enough. If not, repeat the step with the tin foil until the fabric cuts without a problem.