If you are not using pressure washer soap for cars, you can use vinegar. It is a cleaning agent which is used for many purposes. In-home cleaning, it plays a crucial part. Also, it is a natural product. Whether it is dirt, grime, or debris, you can use it without any worries. And not only for pressure washing, but it is also used to clean your foggy headlights and windshield. If you are afraid of chemicals harming your car, vinegar is your best solution. For cleaning the car, go for white vinegar. Do not make it a habit, though. Use it occasionally, say if you run out of pressure washer soap for cars.