It is normal for Vajrayana Bodhi to have cracks. Vajrayana Bodhi is the seed of plants. Generally speaking, it is normal to have cracks on it after playing for a long time. It may be caused by overexertion when brushing your teeth. Usually, it is best to brush along the lines on the surface, or poke the dirt inside with a brush, so as to achieve the cleaning effect and prevent cracking.
It may also be caused by long-term exposure to a large temperature difference in the late stage of playing, especially in the northern region. Cracking of Vajrayana Bodhi is a very common phenomenon. It is best to wear it when going out in winter, or keep it sealed at constant temperature to prevent cracking.
King Kong Bodhi is afraid of high temperature environment. If the weather is dry or exposed to the sun, it is easy to cause surface cracking. After washing, dry it in the shade. When the weather is hot, spray some water on the surface properly, or put it on your palm to play.