In the study, the authors treated samples of Indiana limestone (oolitic) and Vicenza limeston (fossiliferous) with methyl trimethoxy silane (MTMOS), Dri-Film 104, a mixture of Acryloid B72 in MTMOS, and a mixture of Acryloid B72 in Dri-Film 104. The scanning electron microscope revealed that all four treatments penetrated the stones to the same degree and that the difference between Dri-Film 104 and MTMOS was that the former, a partially pre-polymerized resin, was essentially deposited in place without bonding to the stone, while the latter polymerized in place forming a network around the stone particles. Thus Dri-Film 104 coatings can be removed by solvent several years after application, while MTMOS coatings are not removable. See also AATA 16-1622 for related study and 21-1334 for entire proceedings. -- AATA