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diff --git a/shared/clear.s b/shared/clear.s
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+;; Clear the first nametable by resetting it to the default tile ID. This is a
+;; rather drastic measure only to be done on examples that don't actually load
+;; columns in "clever" ways, but they just want a clean slate.
+.macro CLEAR_SCREEN
+    ldy #$20
+    jsr clear_screen_y
+.endmacro
+
+;; Clear the given two nametables. `ONE` and `OTHER` have to be the high byte
+;; for each nametable to clear. For example, on an horizontal scrolling game:
+;; `CLEAR_SCREENS $20, $24`.
+.macro CLEAR_SCREENS ONE, OTHER
+    ldy #ONE
+    jsr clear_screen_y
+
+    ldy #OTHER
+    jsr clear_screen_y
+.endmacro
+
+;; Clear the nametable with the high byte as defined in the `y` register.
+.proc clear_screen_y
+    bit $2002
+
+    ldx #$FF
+@loop:
+    sty $2006
+    stx $2006
+    lda #$00
+    sta $2007
+
+    dex
+    bne @loop
+
+    iny
+    cpy #$24
+    bne @loop
+
+    rts
+.endproc