Library /sys$common/syshlp/mailhelp.hlb SET-SHOW, WASTEBASKET_NAME, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 foldername

    Indicates the name that replaces the name WASTEBASKET for the
    folder containing deleted messages. You can use any alphanumeric
    string for the new WASTEBASKET folder name except MAIL or
    NEWMAIL.

    A folder name can be 1 to 39 characters in length. Valid
    characters for folder names are alphanumeric characters, dollar
    signs ($), and underscores (_). If your folder name contains
    lowercase letters, spaces, or special characters, the folder name
    must be enclosed in quotation marks.