In my experience, it's saturated, but it washes out clean. It also has cleaned my pen converters and ink windows of any staining if it sits in them for around 2 weeks or longer.
That's true, didn't notice any Petrol staining of clear plastic parts. Unlike others which had turquoise or greens, there's noticeable tinting.
My pens were dried to a crust literally there's crystals of sediment. By the labels of the ones I bothered labelling, most were last filled in 2017. I definitely haven't washed anything in the Wash bucket all year.
If I planned ahead I'd have filled them all with water last week for a longer soak. Before opening them up and flushing, then multiple cycles in the ultrasonic. Very therapeutic watching wisps of ink rising out in the jiggly spa bath.