Most all my designs are made from 100% cotton fabric, so I recommend hand washing with a mild detergent such as Dreft or Woolite to keep the colors vibrant.
If using a washing machine, I recommend placing the collar/leash in a laundry bag or pillow case (use a string or rubber band to close the end). This helps protect the hardware as well. Wash in cold with like colors on the gentle cycle with a mild detergent. Hang or lay the collar flat to dry. Please note that cotton fabrics will fade with repeated washing and metallic and glitter designs may fade or lose their "sparkle".
Warm Iron if needed. I recommend covering glitter and metallic prints with a soft cotton cloth when ironing to protect the designs.
IMPORTANT: METAL HARDWARE SHOULD NOT BE EXPOSED TO SALT WATER