The "water bucket" car washing method doesn't quite cut it. Given how dirty a car can get, a few gallons of water from a bucket won't suffice to thoroughly clean it. The likely outcome is a sponge teeming with grime and grit, effectively turning it into sandpaper that could harm the paintwork.  For a top-notch home car wash, you need a giant sponge, a bucket of soapy water - either dish soap or a car cleaning solution will do - and a continuous water supply, whether from a simple garden hose or pressure washer. Begin from the top and gradually move downwards, frequently rinsing your sponge to eliminate harmful substances.  After you've given everything a good scrub, hose down your car and immediately start drying it with a chamois cloth to halt watermarks. Despite doing everything manually, you can efficiently complete the entire routine in a brisk 20 mins.