Physical and Mechanical Methods for the Removal of Lithobionts—A Review

Abstract

This paper describes and discusses the results of scientific experiences of the physical and mechanical methods used to control and inhibit the growth of lichens and biofilms that grow on indoor and outdoor historical stone artworks. It provides an extensive selection and examination of international papers published in the last two decades on the issue. The great advantage of physical and mechanical methods lies in the lack of potential risks associated with the irreversible application of microbicides. Indeed, they do not introduce any harmful chemicals to humans, to the environment, or to heritage objects. This review focuses on the application of (i) electromagnetic radiation, (ii) high temperatures, (iii) lasers, and (iv) mechanical tools, and includes the main achievements, limitations, and potential applications of the examined studies.