Abstract: It is possible to determine whether the correct business form parts have been properly provided in an outgoing package (e.g., mailing envelope) containing a plurality of parts, utilizing a magnetic detector capable of detecting magnetic toner within the package. Dense patterns of magnetic toner are imaged on portions of each of the business form parts, located at different positions on different parts. Then the parts are formed into a package (as by folding about fold lines into a self-contained mailer, or inserting into a mailing envelope), and the package is moved with respect to a magnetic detector. The magnetic detector senses the dense magnetic toner patterns within the package to determine whether all the correct parts are properly in the package by determining whether all business form parts in the package have the detectable magnetic toner indicia patterns on the predetermined portions.