I recently purchased a private collection that included many (over 50) individual selections published by the Art Publication Society from about 1912 to the 1930's, including pieces by Godowsky, Gurlitt, Czerny, Bellini, Balfe, Chopin, Schumann, many by Burgmuller, Streabbog, and I have one of the Exercises series ("Arpeggios of Major and Minor Triads" - Godowsky). The collection also includes several pieces for children.
Although I play, my circumstances dictate that I sell them, which I plan to do on ebay. (However I'm keeping most of the JS Bach--cannot part with them!) Most are in good condition with no markings, just some edgewear and browning of the paper due to age. Before I put them up on ebay, if anyone from this forum wanted to email me privately about purchasing any of these (I was planning to sell them individually rather than as a collection, but we can discuss it), please feel free to contact me at Jubercat20@hotmail.com. I'd rather not photocopy them, so please do not request it; I'm trying not to touch them at all because some of them are fragile and tear easily.
I also discovered a really charming "pack" (they are mostly individual pages, no longer bound) of children's compositions from the APS that include lovely b/w and color drawings (some by an artist named MacGregory, some by T. Baetz, and others). These are all 9x8-some are listed by "Composition No." and some by "Catalog No." There are more pages with drawings than pages with music. I haven't had a chance to look up anything about these, so if anyone has knowledge of them I'd appreciate any info you have. I'm not sure that I want to sell them, but I'd love to know about them.
BTW, I sincerely hope my message is not in violation of posting rules; I could not find an obvious forum FAQ or rules saying no posts about sales, but I may have missed it, so if this is in error I do apologize, and I hope the moderator will feel free to remove it.