Hunt for the security thread. A $100 bill printed immediately after 1990 should have a security thread about the still left-hand side that is certainly only noticeable any time you keep the bill approximately the light. Reaching persistently low amounts of counterfeiting is critical to sustaining self-confidence in bank notes. https://checkbookmarks.com/story2426137/the-5-second-trick-for-how-to-detect-counterfeit-bills