Previous papers (see <i>AATA</i> <b>26-1312</b>) have reported the results obtained on various stones after aging, of the efficiency of the protective treatments, isobutylamide or the isobutylester of perfluoropolyethers over a brief period of time. This report on Carrara marble and on Pietra Serena offers results from a period of about 30 months. All treatments had been performed using 40% solutions of the functionalized derivative in perfluoropolyether. This study isolated the pure ester and amide and tested their performance when used pure. The results obtained show that the performance of the pure compounds is not very different from that of their 40% solutions in the non-functional perfluoropolyether.