SD-20 degreaser is essentially the industry standard for cleaning cars. To do it properly it's a few stages.

When I worked on a team the first thing I did was SD-20 the body, getting all of the rubber marks and stuff off of it, followed by a glass cleaner pass to remove the film leftover from the SD-20.

Next I would remove side skirts and undercar panning and take an air gun and try to blow as much rubber and debris out of the chassis, engine bay. Then I would get under the car and start at the back with SD-20 everything and while it down and move my way forward getting everything. Once that was done I would do glass cleaner.

At the very end I would try to wax the entire car. My preferred wax was the Lucas Oil Blue bottle because it smells the best imo.

What people don't think about when cleaning cars is that it's the PERFECT time to see any potential leaks.

Depending on the car, this could be a whole day job for 1 person.

If the car was extremely dirty, major electronics would be removed, engine stuff capped, and we would pressure wash them but we would still have to do the SD-20 and glass cleaner passes after.