A group of limestone reliefs, (Harvard University, Kevorkian collection), deterioration through salt efflorescence, had to be consolidated. Criteria are outlined for choosing a consolidant and deciding how to huse it. Ten consolidants, either acrylic or silicon based were tested. Choise was controlled by the stone's need subsequently to withstand fluctuating museum temperatures and humidities; therefore the consolidant should either resist pressure from salt hydration and crystallisation or allow removal of the salts from the stone once its friable surface had been consolidated. Surface appearance, porosity (using sems), penetration into stone, water repellance, colour change, hardness and salt recrystallisation were considered after the treatments. An acrylic, acryloid a-21 (polymethylmethacrylate-based) gave perhaps the best results. Scanning electron micrographs; references.