What type of article can potentially have a non-machinable surcharge?

A letter can potentially have a non-machinable surcharge due to its size, shape, or weight. The United States Postal Service has specific criteria to determine whether a letter is considered machinable or non-machinable. A machinable letter meets standard dimensions and weight requirements, allowing it to be processed automatically through the postal machinery. However, if a letter has characteristics such as being too rigid, too thick, or having unevenly positioned elements (like large attachments), it may be deemed non-machinable.

In such cases, a surcharge is applied to account for the additional handling required to process these letters manually. This policy is in place to ensure that the postal system operates efficiently and cost-effectively while providing accurate pricing for different service levels based on how easily an item can be processed.