The purpose of surface cleaning is to remove deposits that might cause damage through abrasion, absorption of acidic gases, or serve as medium for mould growth.
Simple dry cleaning of surfaces using erasers and sponges requires contact with surface which might also cause alteration of surface properties (flattening, eraser residues). With respect to basic requirement to avoid material degradation an alternative non-contact method might be CO2 snow jet cleaning performed using a Precision Spray Cleaning Pen (SnoPen SP 2000, Cleanlogix).
Artificialy soiled samples of wood-based and cotton-based paper were cleaned by the CO2 snow jet with a carbon dioxide flow rate of 3.0 g/s and a nitrogen flow rate of 1.4 l/s and by the nitrogen jet at the same flow rate. Paralel samples were cleaned by traditional mechanical cleaning methods. The effect of treatment was evaluated by optical microscopy.
The results showed that the CO2 snow jet cleaning effectively removed particles in the lower layers of the paper surface, including interfiber spaces.
The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the paper surface. It was proved that the CO2 snow technique is a suitable method for cleaning common types of paper materials.