I used sperm oil in the early 70's. I expect I got it from my new friend, Lester H. Hawkes, who had been shooting smoke-poles since the late 40's for sure, but likely before that as he grew up in the hills of Tennessee, before moving West to Montana.
A stint in the Merchant Navy, shipping out of Seattle iirc, during the WW11, interrupted his BP shooting for a while.
The sperm oil was OK - nothing special for me. I think Track's Mink Oil is just as good, as well as Neetsfoot oil. Bear grease also worked, but in those years I was just learning about tight loads. Today, mink oil and Neetsfoot oil work for all-day shooting, no cleaning needed, just as when using a water based oil.