I used Crisco over the ball on BP revolvers when I didn't know any better.
The whole gun became a black, slimy, filthy, gummed up, barely useable disaster very quickly
with that. Later, reading Elmer's book, he mentioned making greased felt wads to go under
the ball, and I tried Wonder Wads. Wow, was THAT a revelation and an improvement.
Just like Elmer said, you can shoot half a day and the gun is pretty clean and does not
start to bind up like with the Crisco.
The Crisco was allegedly there to prevent "chain fire", which seemed strange since the
ball is oversized and a ring of lead is sheared as you seat it, making very tight seal.
Turns out the chain fire problem was caused by oversized #11 caps (the only ones
available in the 60s and 70s) needed to be squished a bit to stay on the #10 size
nipples. So there was a path for flame to the next cap......and THAT will cause a chain
fire, although I have never had one, and use the proper #10 caps for many years.
Bill