Martin these products are supposed to be water-less or at least used alone. So therefore they are designed to clean a vehicle that is dirty. Least that's how I read it....
So why wash a vehicle in the normal way and then use them ? Surely there would be no purpose ?
We accept (I think) or at least I do spraying them onto a dirty vehicle then rubbing the stuff in is not going to end happy..
No I wont clean a vehicle unless I have access to right kit while I'm away. That said it is possible to visit a jet wash at a garage then set up on site and finish the task there. But I would be using very soft micofibres and a good lubricating detailing spray. No way would I be spraying anything on a surface that was not free from dust and grime.
I have used Greased Lightening but as others have said I rinsed the car first to remove any surface grit the same as I would do if I was going to do a detergent wash on the car, I then applied the greased lightening and found it so so easy to polish it up afterwards, that is the purpose of why I rinse first then use the solution.