bazzer:DravidDavid:bazzer:clevedon:MikeB4: I wash and rinse small areas at a time starting from the bottom of the car working my way to the roof, this allows the dirt to easily rinse off over the clean non stick surface.
It is universally recommended to always start washing at the top of the vehicle and work your way down.
I guess not "universally".
How do you do it?
Bottom up. You?
1. Engine bay first (if required)
2. Door jambs if they are particularly dirty/moudly. (separate colour coded cloth so I know what it's for)
2. Wheels (if I'm using chemical wheel cleaner and definitely with a separate cloth/brush)
3. Roof downwards with my wash mitt.
I usually vacuum the interior first to prevent electrical stuff getting wet on the ground.
If you start from the bottom, you drag road dirt/grit/tar and other problems to the top. You risk scratching the paint with the extra stuff in your wash mitt. Even with the two bucket system, you can still pick up grit from your rinse bucket (which is why it's recommended to get a grit guard) so avoid touching the bottom of your bucket with the wash mitt. :)
The preferred method is pressure washing majority of the grit and tar (in the nicest possible way) and washing with a wash mitt from the top down. This allows the clean suds to wash down the vehicle breaking up any dirt that you will be wiping away later which also helps prevent scratching. It also prevents stuff like mud from getting in to your wash bucket early on and scratching the rest of the car.
If you are doing a cut and/or polish, a clay bar is a must. Some vehicles you can get away with claying the car to remove anything your wash mitt couldn't. If you don't clay your car, the cutting pad will absorb the fine imperfections left after a wash and scratch creating more swirls and scratches.
If you don't have a pressure washer and want to start at the bottom to remove stubborn dirt, perhaps use a separate cloth and bucket after hitting it with a hose so it does not contaminate the wash mitt you use on the rest of your paint. :)