Minimally invasive desorption electrospray ionization-mass spectrometry (DESI-MS) and laser ablation electrospray ionization-MS (LAESI-MS) were used to look for soluble cellulose degradation products produced by accelerated aging in unsized cotton paper. Soluble extracts from papers aged 144 to 26 856 hours were first analyzed in solution using traditional electrospray ionization-MS (ESI-MS). Results were compared to those from direct analysis of condensed phase degradation products extracted from the absorbent paper substrate using DESI-MS and LAESI-MS. ESI-MS results showed evidence of oligosaccharide degradation products ranging from cellobiose to cellononaose; using DESI-MS and LAESI-MS, products from cellobiose to cellodecaose and glucose to cellooctaose, respectively, were observed. As degradation proceeded, increased quantities of both low and high molecular weight oligosaccharides were observed. The analytical approaches developed in the control study were applied for the detection of degradation products in two naturally-aged books dating from the 19th century, both made from cotton and linen. Oligosaccharides ranging from glucose to cellopentaose were observed.