Robin Henderson wrote Southgate, for his patch lube, used Ivory liquid soap mixed with water. In preparation to experiment with Royland's suggestion I've been looking into Ivory to determine if it has been reformulated since the 1950s, so far I can't find anything suggesting it has.
Now I understand this is a muzzleloading, not homemaking, forum however I found the attached screen shot, I'm getting better at screenshots, of an old Ivory ad interesting. Keep in mind Ivory was invented in 1878 and one of it's attractions was in bar form it floats. At a time when many folks bathed in rivers, stream or lakes if the bar was dropped it would float making it easy to find. Anyway note the scene in the ad, tent, rifle, pistol on the user's hip and so on, reminiscent of an old Winchester or Remington ads. I doubt you'd ever find a gun in a soap ad today, unless the advertisement was for cleaning Chicago sidewalks.