Originally Posted by Auto Concierge

I know lot's of people do this(pressure wash the engine) and get away with no problems most of the time(if they cover sensitive electrical areas) but Imo it is not advised. Over the years I have picked up new clients from time to time because the previous detailing service did this and fouled the plugs or worse, various safe degreasers and mild cleaners should be used by hand(takes longer)but I have never been"one of the detailers" told to never come back on a job...........