Development of new methods of cleaning of library and archival collections is one of topics of the Department of Aerosol Chemistry and Physics. The cleaning of particles from book and archival documents surfaces using a two-phase spray of CO2 snow particles in carrier gas stream was investigated under the grant of the Ministry of Culture (DG18P02OVV048 – Research and development of advanced techniques of cleaning of books and manuscripts) in cooperation with the National Library of the Czech Republic. The measurements included characterization of the jet properties, determination of the cleaning efficiency, and evaluation of any possible adverse effects. The cleaning process was automatized. The method was compared with nitrogen jet cleaning and dry cleaning by commercial materials. The results showed that the CO2 snow jet is able to effectively remove particles from the surface and did not cause any observable degradation. The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the surface. It was proved that the CO2 snow technique is a suitable method for cleaning of library and archival objects.
Video: Automatic cleaning of a historical book by the two-phase spray. The book was long-term stored in a depository of the National Library in Prague (Czech Republic). The whole depository was flooded in 2002 during the Vltava river floods. The book was contaminated by muddy water and subsequently only dried.
Figure: The treated part of the book before (left) and after (right) cleaning.