This paper reviews stray light phenomena (SLP) existing in a military platform and compares a classical method with a proposed new concept. The methods used are described as well as the ensuing tests and results. Specifically this paper deals with sun glare and ways to treat it in an airborne FLIR systems having a stabilized line of sight. Besides the obvious direct glare that appears when the sun is in the field of view, there is also an indirect glare originating from stray light due to internal reflections and scattering that appears even when the sun is out of the FOV. The classical method to deal with SLP is to use SLP software in the optic design phase. At times even after careful and organized computer simulation design some unexplained SLPs still appear. The new two-stage method developed to deal with the SLP includes the following iterations: A. Mapping all the appearances of stray light within the space around the system. B. Dealing with each stray light appearance by opto-mechanical corrections and returning to stage A to ensure that no stray light exists. These two stages were iterated automatically in a computerized laboratory setup opposite a sun simulator lamp. The results achieved up to now will be described.