The kitchen sink wasn't draining so I went looking for a cleanout - a plug in the drain line you can open to clean out a blockage. The tool used for this is called a snake and if you have a 88 year old house like me then you've probably had to use one. It's a cable that has a coil on the end and it works really well and is cheap.
Unfortunately, the sink didn't have a cleanout and now I will show you why that sucks so bad... because you can't snake it, you have to cut in a cleanout.
I got it in there, opened the cleanout, snaked it, and it drained. Save yourself 4 hours and put in the cleanout to begin with.
I hooked up the other sink drain and now I'm done... I hope.