White mud on the male genitals is foreskin or urine scale. This condition often occurs in patients who are circumcised or have a prepuce, and the distribution location of the foreskin or urinary scum is usually in the inner plate of the foreskin, close to the inner side of the coronal groove of the glans. When the foreskin is completely separated and retreated to the coronal groove, foreskin scum or urine scum will be revealed, and the taste is pungent with a bad odor. It can be removed by washing with detergent or cotton swabs. However, in some cases, the inner plate of the foreskin and the glans are more tightly adhered to each other and cannot be retreated to the coronal sulcus to be measured, in which case it is not easy to remove. It is also recommended to regularly wash the foreskin scales in the coronal sulcus to maintain personal health and hygiene. Urine scale can be retreated to the coronal groove by the foreskin during urination, after urination will be residual urine stains wash or wipe clean, to do daily cleaning up to two days a cleaning. Finally, it is recommended that patients with a long foreskin or a tight adhesion between the inner plate of the foreskin and the glans undergo surgical circumcision. This can reduce the production of circumcision and urine scale, easy to clean and also can prevent local infection, which in turn reduces the incidence of penile cancer.