Cactus rot

It has been a wetter than normal year in most of Oklahoma. My sister just got interested in succulents and cacti recently and has some of her plants out on her front porch for the warm season. When I was at her house a few weeks ago she pointed out one of her new cacti that was in bad shape. I'm afraid this plant was getting a lot of runoff from her roof and was just too wet. She mentioned it was actually her favorite and she was hoping it wasn't a goner.

The central growth had rotted and was just a black mushy clump with spines. However, it looked like there may be some salvageable growth that had not begun to rot - yet.

I gave my sister some instructions on what to do and then asked if she'd like me to do it. She was happy to hand it over. I took it home, donned some gloves, and carefully unpotted it. I separated the healthy green growth from the black mush and threw that away. I was going to set the green growth aside to let it callous before planting it again, but it seems to be without wounds and had roots attached, so I carefully repotted those growths. Important: I did not water the pot and I sat it aside in the greenhouse in a location where it will stay dry.

I will check this pot regularly over the next several weeks and hopefully not see any new rotting. Assuming all is well, I'll add some rocks to the surface of the soil again and take it back to my sister.