The intent of this research, performed at the laboratory of paper and leather conservation in torun, poland, was to find a simple and inexpense chemical treatment for disinfecting paper infected with mould. A quaternary ammonium salt (quas) solution removed dirt and fungal deposits easily; the paper should be thoroughly washed after disinfection. Results are given for the effects on the physical properties of the paper, the conditions of elution of the compound from the paper, and the influence of quas residue on the properties of paper after thermal ageing. References -- ICCROM