I wear knit shirts mostly and the collars often form a crease in the wrong place, causing the collar to look ugly. When I wash my shirts and put on a hanger I try to remember to leave the collars standing up, so they do not crease, but forget, and I have many shirts with poor crease lines in the collar.
What is the best way to prevent collars from creasing, and is there any way to fix shirts that have bad creases in the collar?