Collars should sit comfortably on the body, with no creases, latent cloth or stretches. Collars may become ruffled over time and need a slight refashioning. One option is to shrink the collar using household washing materials. Decreasing the collar of a shirt will reshape the collar fibers and reestablish a close knit in the fabric. This technique works best with cotton and cotton blend materials.
Fill a sink with piping hot water and add a few drops of liquid detergent to the mix. Dip the collar of the shirt into the hot water mixture. At this point, you can drape the body of the shirt over the side of the sink to avoid letting the rest of the cloth come into contact with the hot water. Be sure that only the collar sits in the hot water. Allow the collar to soak for about ten minutes.
Rinse the collar using a fresh batch of piping hot water. Place the shirt on a sturdy hanger. Use a blow dryer on the highest heat setting to dry the collar. Place the blow dryer very close to the fabric of the shirt collar. Make sure the collar is completely dry before you finish blow drying the fabric.
Use an iron to flatten the collar and make the fabric consistent. Use a moderately hot setting for a just a few seconds on each area of the collar.