A strange mark on a $20 bill might catch a collector’s attention, but not every unusual marking makes money more valuable. Some bills are worth more because of genuine printing errors, rare serial numbers, or exceptional condition, while ordinary stamps, pen marks, and doodles usually add little or no value. In the article’s hypothetical example, a collector offers $250 for a marked $20 bill with other distinctive features, but such prices depend on rarity, authenticity, and demand. If you find an unusual bill, set it aside, check its serial number and printing details, and consult a reputable currency expert before assuming you’ve discovered a hidden treasure…
