The basic material of library collections is paper. There occur also other kinds of materials in libraries, especially collagen materials – parchment and leather, but also textile, and in modern collections also plastic. Project "Advanced techniques of cleaning of books and manuscripts" (identification code DG18P02OVV048) is supported by the Ministry of Culture of the Czech Republic in 2018-2022. The main goal of the project is to develop techniques suitable for cleaning of the mentioned library materials by laser and by carbon dioxide snow. Cleaning will be carried out on model samples at first, then on real library objects. To optimize parameters of both cleaning techniques, it is fundamental to select method of evaluation of their effectiveness in removing dirt and dust, and at the same time the method of observation, whether undesirable changes in cleaned materials do not occur during cleaning, i.e. their degradation. For orientation evaluation of effectiveness of cleaning, measurement of colour scheme was used in L*a*b* colour space, in particular evaluation of parameter L*. Multifunction microscope Hirox serves for measurement of roughness and wetting power of material surfaces, which may change as a result of damage of integrity of collagen fibres. Also use of scanning electron microscope imaging is of advantage for finding the degree of deterioration of integrity of collagen fibres. Degradation of leather and parchments will also be monitored by measurement of changes in shrinkage temperature using hot table microscopic technique.