The answer as it turns out, is “not hand washing”
Hand washing can leave scratches as deep as 1/10th of the paints total thickness. Inconsistent amounts of soap & water and fine particles in sponges/ brushes turn manual cleaning into sanding and ruin your car’s finish.
Source: University of Texas at Arlington, Texas - download
Maintenance goes beyond oil changes and tune-ups. Keeping a car clean is essential and not just for cosmetic reasons. If a vehicle isn't kept clean on a regular basis, it will be de-valued at the time of trade-in or resale. According to auto trade-in experts, cars in excellent mechanical condition and appearance can be valued as much as $1,500 higher than those in good or fair condition.
Source: International Car Wash Association
Motorists wash their car less in the winter months than in summer. Yet cars require more washes in cooler months and when that doesn't happen, the resulting damage often goes unnoticed until it's too late for a cheap fix.
"By far, salt is the biggest car culprit - it can attack even the toughest paints and finishes if not washed off consistently, This winter, getting your car washed at least once or twice a month - or more if you see or feel build-up - is essential to protect your investment." Drivers should be wary of the following car culprits this winter,
Source: International Car Wash Association
Car owners and drivers take the following actions this winter… Be a step ahead of winter visit a professional car wash at least once or twice a month or more, depending on local weather conditions.
First, household glass cleaners are fine, but don't always work well in the automotive environment where bug splats, road tar and streaks are your biggest enemies. The same goes for the old newspaper and vinegar-water solution method. You may end up getting more smearing.
With the side windows partly rolled down, clean the top edges and next to the rubber gaskets first. These tend to be the dirtiest parts of the window and should be cleaned with a separate cloth before you tackle the main part of the glass. Spray the glass cleaner on your cloth and not on the glass itself to avoid overspray on the vehicle's painted surfaces.
The proper way to clean your rear window is by wiping parallel to window defrost lines. If you rub vigorously in the wrong direction, you may risk catching on any cuts in the tinting film and tearing the film.
Be cautious of tinted windows. The quality of tint films varies widely and some films are easily damaged. Always use a product that specifies safe for tinted windows and follow recommendations of the film manufacturer.
