*2.2. Chemical and Electrochemical Solution Cell Fabrication*

To clean the daguerreotype, two cells were designed using Autodesk Inventor Professional 2020, and were 3D printed from UV-cured resin (ANYCUBIC Photon UV 3D Printer, ANYCUBIC 405 nm Resin Green) for chemical and electrochemical cleaning. These cells were designed to be clamped against the face of the daguerreotype, compressing an O-Ring and creating a tight seal with the surface. Both designs exposed a small surface area of the sample surface to the solution, allowing for multiple reagents and techniques to be tested on localized regions of the same specimen. The chemical cleaning device was composed of three solution wells in proximity, allowing for the simultaneous testing of multiple solutions on a localized area. The electrochemical cell incorporated a much larger solution volume, accommodating a three-electrode electrochemical setup [13]. These arrangements are displayed in Figure S1.
