Severus checks it in brewing gear; all charcoal-dark but no robes, and his outer layer a black herbologist's apron rather than the usual waistcoat, sleeves laced tight to his arms. He doesn't really want to know whether it was Poppy or Horace or someone else who had kept his old things or why, but he is glad to have his stillroom apron back. "Lucius," he confirms as he opens it--not that anyone else knocks like that, but he has been telling a few people of his existence and one never knows until one's made sure with a little subtle wandwork. "Come in; I'm at the cauldron, but it's nothing foul."