Animal mummification was commonplace in ancient Egypt, with the remains of many animals placed inside statues or votive boxes with representations of animals or hybrid human-animal creatures. Votive boxes were made from a variety of materials and often sealed; some boxes are still preserved in this state in museum collections. A prior study of sealed copper alloy votive boxes from the collection of the British Museum used X-ray computed tomography to search for animal remains, where poor image quality resulted due to attenuation from the boxes and apparent dense metals inside. In this study, neutron tomography was applied to six of the votive boxes previously examined. Animal remains, likely from lizards, and fragments of textile wrappings were discovered inside three of the boxes. Evidence of the manufacturing process and subsequent repairs of the boxes were uncovered by neutrons. Significant quantities of lead were also identified in three boxes. The findings demonstrate the effectiveness of neutron tomography for the study of mummified remains inside sealed metal containers, and give evidence linking the animal figures represented on top of votive boxes to the concealed remains.