if you do not have a air compressor you can go to walmart and buy a portable compressed air tank. most of them just have a tire inflation fitting take that hose off and buy a cheap hose and air blower then you can go to the gas station and fill the tank for 50 cents then you can blow the car off a few times most likely on one tank
I've used two different products, both of which have done a very good job. First being MOO-tor Cleaner and Degreaser from @The Cow. The second being a mixture of simple green and water in a spray bottle.
Different products for different areas of the vehicle. For metal I like Dynamite Magnum Force 2 contact cleaner, and TrakPower products for plastic. Simple Green for tires, and Invisible Glass for body. Blow it down with my air compressor - good as new. .
I'd suggest using caution with the simple green...this is an aqueous alkalin solution & may negatively impact any aluminum components if not used with great care. I do not use water - just compressed air then periodically, I break the car down fully to check on diffs, drivetrains, bulkheads, etc. when I do the breakdown, thoroughly clean individual parts (e.g., plastics cleaned separately from metal parts, etc.) to avoid corrosion issues & lube all metal/metal components, etc.