The conservation of mural paintings on plaster substrates uncovered during archaeological excavations, particularly those executed in watercolor, tempera, or oil-based techniques, necessitates a comprehensive understanding of plaster’s properties and its interaction with environmental factors. Plaster, as calcium sulfate dehydrate (CaSO₄·2H₂O), is a crystalline and porous material that poses unique challenges in restoration due to its high sensitivity to moisture, temperature, and biological agents. These characteristics, combined with the diversity of pigment layers and organic or oil-based binders, demand multifaceted conservation approaches. This note seeks to problematize the issue in a general sense while highlighting some common challenges and solutions.