Abstract: Methods for coating acoustical surfaces without substantially clogging the pores and reducing the sound absorption characteristics. The compositions applied to the surfaces of the acoustical materials in the coating method comprise an aqueous mixture containing a disinfectant, a pigment such as titanium dioxide, a quaternary ammonium compound of the following formula ##STR1## wherein R.sub.1 is an aliphatic hydrocarbon containing from 16 to 20 carbon atoms, R.sub.2 is an alkyl group containing from 1 to 3 carbon atoms, and R.sub.3 is selected from the group consisting of R.sub.1 and R.sub.2, and an air freshener.