The document summarizes the PACSCL/CLIR Hidden Collections Processing Project. The project partnered with 25 special collections libraries in the Philadelphia area to process and catalog approximately 120 previously unprocessed collections totaling around 4,000 linear feet. The goal was to make these "hidden collections" discoverable by creating standardized finding aids accessible through a single search portal. The project utilized minimal processing techniques to make progress on the backlog of unprocessed material in a timely manner while still making the collections useful for researchers.