Even the most carefully cared-for cars will be attacked by rust at some point in time. The tiniest scratch is all it takes for the water in, get on the exposed metal surface, react with the air and turn a surface on your prized four-wheel possession into a flaky, rotting mess.
Naturally, this does not happen overnight. A little surface rust is not going to require you to go to the expense of replacing full body panels, but if you let rust sit, it will eat through the surfaces of your car faster than you can say “useless rust bucket.”
The trouble is, you might not have the time or the money to get that spot of rust dealt with immediately, and if you leave it, the spot will grow. This is particularly the case in damp environments and areas that experience high rainfall, snowfall or humidity levels. If you are in a bind, there is an easy fix that can cost you next to nothing and arrest that rusty rash before it has a chance to ravish entire body panels.
First of all, you have to go to your local auto supply store and buy a touch-up paint in the same color as your bodywork. If this is not a possibility, at a stretch you can use a nail polish that is the same (or near to the same) as your vehicle. Remember, this is a temporary fix. You will also need a nail file or emery board and some clear nail polish or nail polish topcoat.
Next, you need to wipe down the patch of your vehicle that has the rust spot with a dry cloth or some paper towel. It is important to make sure the entire area of and around the rust are completely dry before you continue.
Take the nail file or emery board and then rub the area of rust until you have reached the bare metal. Keep filing the surface a little way past the visible border of the rust because it may have already started to spread under the surrounding paintwork. You want to take this opportunity to catch all of the rust at once.
Rub once again to ensure the surface is clean and dry, then paint a thin layer of your colored paint or nail polish over the entire surface. It is better to use one, two, or even three thin layers than to try and cover it with a single thick one.
Finally, take a good look at the surface and when you have good color coverage when the paint or polish is entirely dry, you can paint on a layer or clear varnish to protect your handy work from the elements.
This is not a permanent fix. The metal panel will still have to be properly repaired if you want to ensure your vehicle stays rust-free for the long haul. However, this will buy you some time and prevent the rust from getting any worse.