Wet cleaning is a crucial step in poster restoration for removing embedded dirt, stains, and acidic residues that dry cleaning cannot address. This careful process involves using controlled moisture and specialized solutions to cleanse the paper without causing damage. Wet cleaning revitalizes the poster's appearance, enhances color vibrancy, and stabilizes the paper by removing harmful substances. It also prepares the poster for further restoration steps, ensuring a comprehensive and lasting preservation of the artwork's integrity and beauty.