These glass eyes are perfect for your BJD dolls. To use them, simply insert them carefully into the eye sockets of your doll. When handling, do it gently to avoid any damage to the glass. As for maintenance, you can use a soft, dry cloth to wipe them clean if they get dirty. Remember, these eyes are only for dolls, not for real animals or humans. Also, keep in mind that there might be a small measurement error (1 - 2mm) due to manual measurement, and the colors in real life might vary slightly from the pictures. Enjoy creating beautiful dolls with these amazing glass eyes!