To investigate the common C pollution phenomenon of the microchannel plate (MCP) with an ion barrier film, we conducted vacuum heating, ultraviolet irradiation, and hydrogen heating tests. Auger electron spectroscopy and MCP electrical performance test are performed on each test result. Furthermore, the trends of MCP C content and MCP performance are analyzed using different methods. The analysis results show that the reduction in C content significantly improved MCP performance. The vacuum heating process does not significantly affect the decomposition of C; however, the UV irradiation and hydrogen heating processes can completely remove MCP C pollution. Finally, hydrogen heating significantly improved the MCP gain performance and resulted in the highest efficiency.