Not only can smegma, a waxy substance that includes dirt and dead skin cells, accumulate, but some geldings (and occasionally, stallions) may also form a 'bean', a hardened ball of smegma inside the sheath or even the urethra that, in extreme cases, can interfere with urine flow. This area may need to be cleaned, starting at a young age after breeding and the birth season, but particularly in geldings. Sheath cleaning is a hygienic process occasionally needed by male horses, both geldings and stallions, wherein a caretaker, groom or veterinarian checks the horse's sheath, the pocket of skin that protects the penis of the horse when it is not in use for urination (or, in the case of stallions, breeding).
