/sys$common/syshlp/helplib.hlb CMS, DELETE, HISTORY, Qualifiers, /OBJECT=object-expression  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies an object about which history information is to be
    deleted. The object expression can be one or more class names,
    element names, group names, a wildcard expression, or a list of
    any of these, separated by commas. If you do not specify an object
    expression, CMS deletes all classes, elements, and group
    transaction records in the library subject to the constraints
    imposed by other qualifiers.