Is your tinted BMW E39 M5 window film turning purple or producing bubbles? Here is a do it yourself site that will guide you in removing your dying window tint.

The tools needed for this job are household items like black thrash bags, undiluted Ammonia, very fine steel wool, razor blade or sharp knife, Windex glass cleaner and a beautiful, hot sunny day.

This site lists down the five steps in removing the old window tint. And if you faithfully follow these instructions, your window will look as good as new after three hours.  By the way, those ugly purple films are caused by non-metallic dyes breaking down and changing color in the film. While bubbling films are signs that the adhesive used to apply the tint to your window is failing.

Visit the following site: http://www.tintcenter.com/articles/bt_removal.html