It is said that the liquid used in the American Gas Furnace or Carbonia process was a mixture of several oils including sperm whale oil and fish oil. It's reported that because of that, the process stunk to high heaven. It was a proprietary process that was a trade secret owned by Smith & Wesson, but Turnbull and others claim to be able to reproduce it. The Carbona process used by Colt reportedly involved heating gun parts in charcoal and rubbing the heated steel with rags soaked in fish oil. This was said to smell pretty strong too.
