I wash my car with a pressure washer. I just spray the car from further away that way the pressure isn't strong and also, avoid spraying the soft top from too close since you wouldn't want any water to leak into the cracks.

 

on a lower setting it will be fine. If you have chips in the paint however it can cause the paint to flake out from the chip. I have a pressure washer and use it on mine with no problem

 

With the paint chips, just spray from further away so that the pressure is spread out and it shouldn't be a problem at all.