I have been "spinning" a recently acquired collection of RCA and Mercury 2-track 7.5 ips tapes on my R2R deck. The RCAs are Chicago/Reiner classics as well as a large group of Dorati/LSO, Dorati/Minneapolis Mercurys, all in their original boxes.
The acetate is in pretty good shape considering a lot of these tapes are 50 years or so old.