One way would be to blank it.

Code:
LCDOUT $FE, $C0, "                "
other fun codes:

$FE, 1
Clear display

$FE, 2
Return home (beginning of first line)

$FE, $0C
Cursor off

$FE, $0E
Underline cursor on

$FE, $0F
Blinking cursor on

$FE, $10
Move cursor left one position

$FE, $14
Move cursor right one position

$FE, $C0
Move cursor to beginning of second line

$FE, $94
Move cursor to beginning of third line

$FE, $D4
Move cursor to beginning of fourth line