The only way to remove a tattoo that you do not like is to either do a cover up tattoo or go and have laser surgery to remove the tattoo. With airbrushed tattoos you can get rid of it with baby oil or just wait about 7 days and then it is gone. No need to go and get an even bigger tattoo to cover up the offending one or go through the hassle of laser surgery. With metal actually being smooth the paint will have a hard time sticking to the smooth surface. This is why it is important to wet sand the metal first. A base coat should be applied to the metal before any airbrush art design is started. Take your time and make sure that the surface you are working on is prepared thoroughly so that the paint will stick. If the automotive paint that you have chosen does not flow then thin it down so that it flows. The paint should be thinned to about a milk thickness. A good automotive lacquer will work fine to thin down your automotive paint. Different airbrush art calls for different psi on your compressor. PSI stands for pounds per square inch and for automotive airbrush art you need a compressor that has a psi of 55-65. Kent Lind will show you how to create cool caricatures in this approximately 70 minute video titled, How to Airbrush Caricatures. This video will go into all the details that you will need to know to create your own airbrush art caricatures. These designs are great on t-shirts, canvas and if you really want you can put then on your car. Continue to practice with shapes until you are able to perfectly render airbrushed shapes. Once you have the ability to render the shapes, you can move on to rendering shapes in different textures. This means that you should work on creating shapes with thin lines and shapes with thick lines. This will help you to learn more how to use the airbrush to render broad designs as well as fine detail. Airbrushing the artwork on took a lot of time out of painting the vehicles over doing the designs by hand. Thus airbrush art was being experimented with on vehicles at this point. The way we use airbrushing now to create art surly has come along way from the primitive methods used by our ancestors and even our parents.