Storage
Although popularly considered a delicate material, silk and silk-wool blends are a very strong fiber that resists wrinkling. However, if left folded up for hours or days, creasing and wrinkles will eventually set in.
To prevent creasing and wrinkling, remove your pocket square when undressing and fold it into a square before storing it in a cool, dark area, like a drawer or cabinet, to protect it from sunlight and dust.
Pressing
If heavily crumpled, you should first attempt to use a garment steamer on a low setting to relax the wrinkles.
If the wrinkles persist, place a cotton cloth on top of your pocket square and then iron on top of it around the center, using the delicate setting.
Do not run the iron over the edges of the pocket square as this will damage the hand-rolled edges.
Cleaning
If your pocket square should become stained or dirty, do not wash it by immersing it in water. Instead, create a solution of tepid water and mild detergent and spot clean the pocket square with a clean cloth as needed.
If the stain persists, take your pocket square to a reputable dry cleaner that specializes in the handling of delicate fabrics.