The degradative changes in silk are investigated with amino acid analysis and solubility under denaturing conditions (7M urea). These biochemical techniques use extremely small samples for quantitative analyses and are capable of detecting chemical alterations at the molecular level. The biochemical results are used to place the fabric samples from a museum collection within the context of artificially aged silks. Analyses of the naturally aged samples reveal two populations: sericin-rich and sericin-depleted. Denaturing solvents such as soap will remove the protective protein coating from sericin-rich fabrics; sericin-depleted fabrics are already a high risk for light-induced damage. The data suggest that silk fabrics manufactured during this century are likely to have their sericin coatings totally removed and are therefore at great risk for light damage.