First, lightly pre-treat visible stains with a stain remover like Shout or Tide (the pens work well!). Allow the stain remover to work for at least ten minutes before hand washing.
To hand wash the embroidered design, use a clean, damp cloth with cool water. It is best to use cool or tepid water to prevent the dye from bleeding.
Be certain that the cloth is very clean and has no residue from cleaning agents that could cause damage to the case.
The cool water should be effective enough for light stains, but if the stain is older or darker, spot clean with a gentle liquid detergent that will disperse with water and leave less residue on the fabric.
Continue to clean using a damp cloth with fresh, cool water on the embroidery until there are no more soap suds visible from the detergent.
Allow drying fully before use.