article_snippet: On Monday, an envelope containing an 'unknown milky substance, in a container wrapped in a plastic bag,' appeared at the the White House Mail Screening Facility, 
article_snippet: Milky Substance:' On Monday, an envelope containing an 'unknown milky substance, in a container wrapped in a plastic bag,' showed up at the White House Mail Screening Facility .
article_snippet: the mail handler allegedly once sent a package to the White House covered in feces and urine.
article_snippet: Then in a 2012 incident, the mail handler sent a package to the White House the White House containing mini alcoholic beverages.
article_snippet: Fox  has previously sent letters covered in urine .
highlights_snippet: Authorities say the White House sender has been mailing packages to the White House since 1995  including ones covered with urine and filled with alcohol .