Using contact will not be foolproof, having said that. The most thriving counterfeiters will bleach serious dollars then print above it. Keep the bill to The sunshine to see the embedded thread left from the portrait. This thread runs vertically down the note and includes “United states of america 5” https://socialicus.com/story2222400/new-step-by-step-map-for-how-to-recognize-counterfeit-bills