Objects associated with Chinese Cantonese opera form one of the major collections of the Hong Kong Heritage Museum. The sequins on one of the Cantonese opera stave curtains are disintegrating seriously; the curtain itself was used as a backdrop during the performance of the opera. In order to understand the possible causes for this degradation and hopefully to devise the proper strategies for remedial treatment and storage, the composition of the sequins was studied using a varied of analytic techniques including Fourier transform infrared spectroscopy (FTIR), x-ray fluorescence (XRF) spectroscopy and scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX). The analyses were carried out on broken sequins that had become detached from the curtain. The results indicated that cellulose nitrate, silver and gelatin were present. As there was little information about the fabrication and the past history of the stage curtain, the complete mechanism for its degradation could not be deduced. It is believed, however, that the deterioration of the sequins is due to the presence of unstable cellulose nitrate, accelerated by the unfavourable environment in which the curtain had been stored. Preventive measures were adopted to retard the deterioration rate of the sequins while considering other long-term preservation strategies.