How do you get wet cardboard stains out of carpet?

To remove wet cardboard stains from carpet, start by gently blotting the area with a clean cloth or paper towel to absorb any excess moisture. Mix a solution of mild dish soap and warm water, then use a cloth to dab the stained area, working from the outside in to avoid spreading. Rinse the area with a damp cloth to remove soap residue, and finally, dry it thoroughly with a towel or fan to prevent mold growth. If the stain persists, consider using a carpet cleaner or contacting a professional.