Polygonal meshes obtained from acquisition of real-world objects may easily exhibit topological or geometrical defects, which often prevent subsequent processing and analysis to provide satisfactory results. This paper describes the foundations of ReMESH, a userfriendly graphical tool which incorporates several meshrepairing features, and allows to perform a kind of lowlevel editing which is often missing in most existing software packages. We show how state-of-the-art techniques have been adapted and extended to form an intuitive and integrated environment, and introduce some optimizations and novel ideas that make ReMESH particularly efficient. The main application in which the tool proves to be extremely useful is the post-processing of scanned surface models. In this context, ReMESH represents a valid support for the production of certified quality meshes.