Classic cars require special attention when being washed. Rust can quickly become an expensive problem when a classic car is washed incorrectly.
Rust is accelerated by the presence of water. This seems like a bit of a problem, because water (with soap) is needed to lubricate the surface of the paint to prevent scratches. Wiping the paint with a dry towel might prevent rust, but it will put horrendous swirls in your paint.
The solution is to use rinseless wash techniques. Traditional soaps dissolve oil, but leave the dirt and dust untouched. Rinseless wash systems use a special soap designed to surround dirt and dust in a protective bubble of lubricating molecules. This means you can spray a rinseless wash onto the surface of the vehicle, and use a microfiber towel to wipe the surface clean WITHOUT scratching your paint. Because rinseless washes use very little water (~12oz per vehicle), it is easy to keep the water away from any exposed metal.
Steps to a rinseless wash:
Spray the rinseless wash solution onto a portion of the vehicle.
Using a damp microfiber towel, wipe the surface of the paint. Flip to a new portion of the towel for each pass. Using several towel is recommended.
Dry using a clean microfiber towel.
Repeat for the rest of the vehicle.
Rinseless washes are quick, simple, and can be done inside the garage (great for hot or cold days). They cannot be used on extremely dirty cars, but are useful for cars that are regularly maintained. We recommend a rinseless wash for all classic cars where rust is a concern.
There are many good brands of rinseless washes available, but the one we recommend is Optimum No-Rinse. A 32 ounce bottle mixes to make 64 gallons of ready-to-use solution. You can see other recommended products on our Recommended Products page.