The VP citrus pre wash is a fantastic product.
It's great value for money as it can be diluted up to 300x (in a PW). I generally us this as the name suggests, as a pre-wash before washing the bodywork. I use a pump sprayer and dilute 1:10 with warm water. This seems to activate the PW and it gets to work straight away on any road grime. Leave to dwell and the power wash off and the car is really clean to begin the hand wash (I'm not a foam guy but this could be incorporated into the process).
That's not all though, it's great on wheels as a pre wash to get the bulk of the grime off and also can be used on the interior on stubborn stains/upholstery. Depending on the filthiness of your car, you can also make the solution stronger by diluting less if the need takes you. I've also started using this to clean my mountain bike and again it does an excellent job. So if your looking for a pre wash treatment that can be used in so many other applications, lok no further than VP Citrus pre-wash. What a fantastic product.