Computer-implemented methods, apparati, and computer-readable media for countering spam that disguises characters within an electronic message (1). A method embodiment of the present invention comprises locating (36) portions of an electronic message (1) where the difference between foreground color and background color is negligible; deleting (37) from the electronic message (1) foreground characters from said portions, to form a redacted electronic message; and forwarding (33) the redacted electronic message to a spam filter (23).