Yep, to rinse out, just pull the injector line out of the soap/sh, and drop it into a bucket of water and allow,the injector to draw water for a minute or so.
As for what eventually kills the injectors, after going through a couple of dozen, trying to figure out what causes them to slowly die, I have filed away the following in my mental database to look for once I detect that it seems not enough soap is being drawn:
1) pitted steel ball. Always replace it with a ceramic one. Once I did this, I've never had to replace the ceramic one.
2) the small oring that the ceramic ball seats against will get gummy....I have a small spray bottle of "goo gone" that I will remove the barb and spray a bit of the goo gone onto the oring and ball periodically.
3) the small orifice insert inside of the injector body.... I've had them simple come loose, by screwing out... It's a threaded cone with Hex wrench head... Make sure it's tight.... I've had them completely come out as well.
4) the orifice insert gets corroded by the SH.... just this week I had an injector that started to lose draw.... I checked the orifice was tite, but then I backed it all the way out and saw the small tail side of the cone was eaten away, and effectively changed the size of the orifice opening..... I had a spare cone with the same size and replaced it, which immediately solved the problem.
5) also check the trash filter at the end of the line in the Sh bucket, metal ones will corrode and break down, causing metal chunks to clog the injector..... Same with the plastic body ones.... The metal screen material breaks down, and corrodes away creating a hole in the mesh screen allowing junk to be sucked up and clog the injector... Always keep spare plastic filters on hand, and inspect daily for damage and replace if necessary.