There is white dirt in the coronal groove, which belongs to foreskin scale. Foreskin scale is mainly lipid metabolites secreted by the inner plate of the foreskin, and these substances accumulate in the coronal groove of the foreskin for a long time to form foreskin scale, which has a special odor. The foreskin scale stays for too long and will stimulate the glans and foreskin mucosa, causing local inflammation. The actual fact is that you can find a lot of people who are not able to get a good deal on this kind of things. If you don’t pay attention to your personal hygiene, you will often have glansitis and even adhesion of the foreskin and glans, patients can usually be treated with circumcision to reduce the production of foreskin scale.