From Dylan at Adam's Polishes Forum [a vendor here]
WHAT ARE WATER SPOTS?
Simply put, a water spot is the stuff that was suspended in the droplet before the water dried/evaporated. Depending on the source of the water and where it had been before drying you can see any number of things cause the actual spot.
Ground water is the most common culprit. The water from a mis-aimed sprinkler or the water used from your hose is full of minerals. The type of mineral and concentration varies from region to region and based on how 'hard' your water is you may see more severe spotting. Rain water typically carries a different type of contamination. As that little droplet fell thru the air it picked up airborne pollution as well as dust or dirt, plus if the water ran off of a tree or nearby roof before landing on your car it took some of the contamination from those surfaces as well. Road water would be the very dirty water that is splashed up behind your wheels or all over the lower regions of your car when driving in wet conditions. Its almost impossible to know what is suspended in that water, but for sure it contains all manner of very nasty dirt, chemicals, and other road grime.
WHAT IS BONDED MINERAL CONTAMINATION?
Bonded minerals are just a more severe form of water spot. When mineral concentrations are higher, or a car is subjected to lots of ground water drying on the surface (sprinklers hit a car every morning) water spots can become bonded minerals. These are a little more difficult to deal with as they form hard bonds with the clear coat that make them harder to remove. Once removed bonded mineral contamination can sometimes leave the area where it was looking dull or even pitted.
WHAT IS ETCHING?
Etching is the worst case scenario in the progression of water spots. Etching is typically seen from water thats baked on in direct sunlight or high heat. It is also prevalent with acid rain or ground water with high levels of chlorine. Etching can be minor to severe, with the most severe kind requiring very aggressive means of correction - potentially wet sanding in extreme cases. Etching is a circumstance where the water spot has physically 'eaten' its way into the clear coat so that it sits at a lower level than the surrounding surface.
REMOVAL METHODS:
These processes are listed in order from least to most aggressive.
Start simple! For lighter spots something as simple as a complete wash or wipe down with Waterless Wash or Detail Spray and a microfiber towel may be enough to remedy the problem. As with any detailing process, always try the least aggressive/simplest method first.
White vinegar can be used for spots that are a little more stubborn and more mineral based. Soak a small area of a plush microfiber towel with the vinegar and wipe the problem area (after the area has been properly cleaned and dust removed) Perform this task out of direct sunlight to avoid complications. Be sure to reapply your preferred wax/sealant to the area as the vinegar will have degraded/removed any protection.
Claying can be very effective at removing water spots. The process remains unchanged from the usual claying process. Adequately lubricate the surface and move the clay back and forth over the area. Be sure to spend extra time working the spots from multiple angles to give the clay the best opportunity to grab the contamination. Repeat uses may be needed in some cases.
If the prior step fails to completely remove the spot then you may be dealing with etching. In this case physical abrasion of the surface becomes necessary to 'level' the clear coat back to the same as the surrounding areas. Follow the same guidelines as when polishing to remove swirls, be sure to use the least aggressive polish to get the job done and always test your process in a 2'x2' area before completing the entire car.
WHAT ABOUT ON GLASS?
The exact same rules apply for glass, but with one exception - glass is far harder than clear coat so it allows for more aggressive options when finer options fail. After attempting the above steps on glass, if you have not seen improvement or complete removal there is 1 more step to attempt.
If auto polishes fail, a more aggressive household abrasive cleanser can be used on glass. Bonami is available at most any store and is very abrasive.
When gritty cleansers won't do the job try using 0000 steel wool and liberal spraying of glass cleaner. Spray a good amount of Adam's Glass Cleaner into the steel wool pad, then spray a few pumps onto the glass. With light pressure scrub the affected areas of the glass. As with anything aggressive be sure to mask off adjacent trim and paint to avoid accidental damage and test an area to make sure the desired results are achieved.
PREVENTION:
As with anything prevention is the best medicine.
On paint maintaining a coat of sealant and/or wax will prevent minor spotting and lessen the impact of more severe conditions. Glass should be sealed as well to give maximum protection.
Remove standing water from the paint, especially on days where the sun is out and don't allow water spots to go untreated for extended periods of time. The longer they sit the higher the chances of a bigger issue arising.
