IIRC, the main ingredient used in so-called stabilization processing was a thiocyanate. I used to use a lot of it when I was in a hurry. I had a stabilization processor with which I was able to do a lot of prints quickly. In most cases, I did this to allow batch fixing and washing of the whole bunch. Once in a while, I let one sit without fixing and washing. After a while, the appearancs was somewhat like sulfide toning, but not good.

That was, I have heard, a lot different from proper fixing and washing followed by thiocyanate treatment for protection. I don't do it any more anyway. Nowadays, I no longer photograph guest artists at Symphony dress rehearsals and come back the next day to play the concert and present the finished pictures, usually working a full day at Langley Research Center in the meantime.