Hi, we kept a dark blue leather suite in a shed which was given to us, whilst we were doing our build. Of course the build dragged on, but we finally got in and decided to bring up the sofa, but it has damp spots on it, like white marks, mildew I suppose. Does anybody know if we can get this clean or would something like saddle soap bring this up like new or is it ruined? Cif, baby wipes etc don't work.