The green tinge that may appear after the application of a Spray on Tan can be caused by a few different factors. Firstly the acidity levels of the skin can react with the spray tan solution. Acidity on the skin can come in the form of salt from the body’s natural sweating process along with more potent items such as deodorants and moisturisers. A solution can also appear green on the skin when the product is out of date or when the solution bottle has been opened and the lid is closed tightly enough, thus allowing for moisture and humidity to affect the life the solution.