Graphite oxide (GiO) and graphene oxide (GeO) possess wide applicability in technological devices. The exact chemical compositions, structures, and properties of these materials remain vague to the graphene community despite being heavily researched. As metastable materials, the properties of GiO and GeO are easily manipulated under various conditions of temperature, light, and atmosphere. Although these aspects are important considerations for long-term storage of the materials, they are not well understood. In this experimental work, investigations are performed to determine how light and atmosphere contribute to the characteristics of GiO and GeO powders. The study shows that, at room-temperature, the quasi-equilibrium states of both materials, in specific the O/C ratios, vary according to the storage conditions. Drastic disparities between GiO and GeO are observed. GiO kept away from light and GeO kept under inert atmosphere maintain relatively high O/C ratios. As the metastable states of the materials are governed by the diffusion of oxygen functionalities, the presence of epoxide groups diminishes while negligible changes occur to the sp(2) lattice size. This experimental work lays out fundamental aspects that govern the stability of frequently mass-produced GiO and GeO powders under different environments, with major implications on their optimal storage conditions.