A new multi-scenario, low-cost, high-efficiency, medium-assisted continuous laser cleaning of corrosion layers was developed. By comparing the roughness and cleaning depth of rust layers cleaned under conditions of liquid-assisted, solid-assisted, and mixed solid–liquid-assisted laser cleaning, simultaneously establishing a three-dimensional finite element model to study the variations during the cleaning process, and conducting a comparative analysis of the results of both, the cleaning mechanism is elucidated. The experimental results indicate that under conditions of water-assisted cleaning, the depth of rust layer increases initially and then decreases with varying water layer heights. The maximum cleaning depth is achieved at a water layer height of 0.1 mm, while the optimal surface roughness occurs at a water layer height of 0.2 mm, indicating a change in cleaning mechanism. The cleaning pattern with SiO₂ activator assistance follows a similar trend to a water medium, reaching maximum cleaning depth at 0.1 mm height, with a slight improvement in surface roughness compared to water-assisted cleaning. Finally, solid–liquid mixing can achieve cleaning completion and improve surface roughness under conditions where water-assisted cleaning alone fails to reach a clean state. Therefore, the active agent can be used for laser cleaning to promote the cleaning process, and solid–liquid mixing to assist the laser cleaning can be a theoretical guide for the field of laser cleaning.