Anyone ever rebuild a pressure washer pump?

I've never had one but I've worked on a few.
I didn't know about any 30 second unloader rule.
In any case, they're really simple little devices and I've rebuilt quite a few. Mostly what I see is is crudded up unloaders running on chlorinated water, which creates a greenish powder, when left to dry out.
I can only imagine what is does inside your body..............