*FULL TITLE* Slimed! Gross 'black slime' creeps over Washington DC's most famous monuments - and no one knows how to get rid of it Read more: http://www.dailymail.co.uk/news/article-3751208/Slimed-Gross-black-slime-creeps-Washington-DC-s-famous-monuments-no-one-knows-rid-it.html#ixzz4I31HktnO Follow us: @MailOnline on Twitter | DailyMail on Facebook Abraham Lincoln and Thomas Jefferson have been slimed. A mysterious black slime has been steadily oozing over Washington DC's most famous monuments, including the Lincoln and Jefferson Memorials. The Jefferson Memorial's white marble dome is slowly turning gray from the icky substance, which is called biofilm, and not actually a slime, but more of a powder, reports CBS News. The black stuff has also...