if you need all object
you cad do it with just delete '((0 . ~~~))
(setq ss (ssget '((0 . "LWPOLYLINE")(8 . "WALL"))))
(setq ss (ssget '((8 . "WALL"))))
or you want all of layer
(setq ss (ssget))
and also ss1
(setq ss1 (ssget "F" co-ord (list (cons 0 "LINE,LWPOLYLINE,ARC,CIRCLE,POINT,TEXT,MTEXT,insert"))))
(setq ss1 (ssget "F" co-ord))
If you want to exclude wall layer from the selected objects
(setq ss1 (ssget "F" co-ord '((-4 . "<NOT") (8 . "WALL") (-4 . "NOT>"))))