Minckler left this collection of music to the Appanoose County Historical Society. Eventually that organization judged it out of scope and, after evaluation by Rick Altman, it was acquired in 2010 by the University. The collection consists of an estimated 3000 scores, existing music (not original compositions) presumably used by Minckler as music director at the Majestic Theatre in Centerville, Appanoose County, Iowa. Most are numbered, suggesting they might once have been coded to a card or other catalog, but a thorough search at the Appanoose Historical Society failed to discover anything that might be even a fragment of such a finding aid. Many of the scores are marked to indicate selected or deleted passages, and there seem to be notes on many that might link them to movies for which they were used. Some are also marked with the time signature, key they are in, and another number which might be the length of time they take to play. Some are also marked with the emotion or idea they are intended to provoke, such as indifference, spritely, mother, and so forth. A good portion of the scores are not marked, however, and do not have Minckler Library stamp or number. Where the number is present, it appears in the citation immediately after the title, and before the date of the piece.