Method of cleaning a bottom plate

A method of cleaning a bottom plate, wherein steps of the method comprising:

• (a) welding a soldering lug:
• welding at least one soldering lug onto an adjacent bottom plate;
• (b) covering with a liquid material:
• filling the liquid material between the adjacent bottom plate and the at least one soldering lug to cover a substance to be cleaned on the adjacent bottom plate;
• (c) placing in a chamber:
• placing the adjacent bottom plate containing the liquid material in the chamber;
• (d) controlling a chamber temperature:
• controlling the chamber to at least one predetermined temperature, the predetermined temperature being coordinated with viscosity of the liquid material, between 25 and 200° C., to increase fluidity of the liquid material;
• and
• (e) intermittent fluctuation cleaning:
• generating intermittent high-pressure pressure increasing and reducing and intermittent low-pressure vacuum pumping for a gas in the chamber using a pressure increasing and reducing device and a vacuum generator, so that gas molecules in the chamber generate a fluctuation airflow through molecular motion, which is fluctuation of the gas molecules between intermittent high pressure and intermittent low pressure, and intermittent fluctuation in pressure ranging from a maximum of 50 atmospheric pressure to a minimum of 10−5 atmospheric pressure, causing a fluctuation change of the liquid material by an intermittent fluctuation change of the gas molecules using high pressure of the pressure increasing and reducing device and low pressure of the vacuum generator, rubbing and scrubbing the liquid material in contact with the substance to be cleaned by fluctuation, and taking the substance to be cleaned attached to the adjacent bottom plate away from the adjacent bottom plate and the liquid material.