You can buy a clay kit, which includes a small bar of clay and a bottle of cleaner/lubricant. The kits are available at many auto parts stores - just ask. It's very simple to use. The kit will come with instructions, but I'll give you the general idea. Give your vehicle a good wash and dry. Working in small sections, no more than 24"x24", spray enough lubricant on the vehicle so that the clay glides smoothly across the surface. Work it gently back and forth. You do not need to apply alot of pressure and do not use a circular motion like you would with a polish or wax. You will see and feel the contaminants lift right off the paint like magic. Buff the area with a clean, dry terry cloth and then begin the next section. Frequently knead the clay to expose clean material. When the bar is dirty, throw it away and replace it. When you complete the first section, slide your fingers across the clayed surface and then across another area that you thought was clean from your wash. You will be amazed at the difference. Those water spots of yours should lift right out along with all the other crap that is adhered to your finish. The concept of the clay is that micro-contaminants and debris tend to resist the lubricant. As the very sticky clay glides across the surface, it picks up the "non-lubricated" crap which is then buried below the surface of the soft bar, leaving a pristine surface. Pretty cool, huh?
And just think of the workout your arms will get. But I'm sure that you've had some similar experience.
