Many museums store land and sea shell collections in wooden cabinets that outgas formic and acetic acid. These acids react with calcareous materials to form efflorescence salts, a deterioration process that leads to eventual loss of collections. We utilized in our present work the well-known method for accelerating efflorescence formation that can be used to evaluate storage conditions, and to determine the efficacy of materials used to protect the objects themselves. We placed a series of test shells in sealed desiccators together with aqueous solutions of acetic acid and/or formic acid, along with magnesium nitrate to control the relative humidity. Acid vapor concentrations are determined using diffusion tubes in combination with ion chromatography. The composition of the efflorescence is determined by X-ray crystallography and ATR-IR spectroscopy. Increasing the acid concentration increases the rate of salt formation. Products that form include calcium acetate hemihydrate, Ca(H₃COO)₂. 0.5 H₂O and calcium formate, Ca(HCOO)₂. Conditions that lead to the formation of calcium acetate formate hydrate, a known efflorescence product, are also being determined. In parallel with these studies, the acid concentrations inside cabinets at the Los Angeles Museum of Natural History have been measured and efflorescence on objects in the museum’s collection characterized. The analysis of the vapor compositions and efflorescence products in both the model systems and museum samples will be presented. This work shows that an artificial environment can be used to replicate and accelerate the efflorescence deterioration process, and can be used to evaluate reversible coatings for preserving calcareous artifacts.