Oh, also... when I was researching PW solvent, all the water based cleaners were eating the paint off the PW after being left in for any length of time. I think the standard mineral spirits solvent is more "paint friendly" than the water based. As mentioned with the Dawn getting "used up" with a lot of grease, same goes for any of the water based cleaners, but they could be very aggressive initially. Not that this matters for filling a tub and dumping it, but if you are considering a PW, I think it pays in the long run to use the traditional real solvent. To phrase it differently, the water based stuff loses cleaning ability as it gets dirty. The real solvent just gets dirty and can be filtered and used for a very long time. I also like not having to dry all the water off of steel parts before they rust.