Oh, I washed our cats many times, but I never did it in the tub...
Use a toothpick or very small instrument to push that spring loaded pin and hold it in, while you push the slide stop back into the frame. That is if I am understanding your query correctly. CCI field stripped my Kimber Custom II and cleaned and oiled it up.
When I started to put it back together, things got a little dicey. I proceeded on and now stopped because I can't get the slide stop back into the slide hole. There seems to be a small retractable pin as a part of the the thumb safety that i can't get it to retract to allow the slide stop to put in correctly.
I have been watching a video. But the camera angle doesn't allow me to analyze what exactly was done to accomplish this.
Any help would be appreciated!