now that i read all the posts, i see that mine is virtually the same as alan's, but i thought i'd post what i did anyway.
(defun process (#ListCompare #ListValues / #NewList)
(mapcar
'(lambda (x y)
(and (not x)
(setq #NewList (cons y #NewList))
) ;_ and
) ;_ lambda
#ListCompare
#ListValues
) ;_ mapcar
(reverse #NewList)
) ;_ defun