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There are currently no universally accepted standards for the cleaning quality of polysilicon production equipment, but inspections can be carried out using the testing methods specified in the following standard: HG 20202-2000 \"Specifications for the Construction and Acceptance of Degreasing Projects\"； HG/T 2387-2007 \"Quality Standards for Chemical Cleaning of Industrial Equipment\" ； DL/T 794-2001 Guidelines for Chemical Cleaning of Boilers in Thermal Power Plants ； Depending on the production process, there are currently two main cleaning grades ； 1. Trichlorosilane method: It is divided into clean cleaning and general cleaning. The equipment and pipelines prior to the distillation process are mostly subject to general cleaning, while the equipment and pipelines in the reduction and subsequent processes (including the CDI for off-gas recovery and the trichlorosilane storage tanks) are mostly subjected to secondary cleaning. 2. Silane method: It is divided into primary cleaning, secondary cleaning, and tertiary cleaning (according to foreign manufacturers’ standards). Primary cleaning applies to silane-based equipment and pipelines; secondary cleaning applies to solvent/mixed solvent-based equipment and pipelines as well as heptane-based equipment and pipelines; tertiary cleaning applies to all other types of equipment and pipelines. Depending on the type of pipes in the equipment to be cleaned, the cleaning processes can be divided into four categories: spray cleaning, circulation cleaning, immersion cleaning (tank immersion and pouring immersion), and wiping cleaning. The pure water used for cleaning is tested and meets the requirements: oil content is zero, conductivity