diff --git a/button.c b/button.c
index 805a51e9..2a5d5cca 100644
--- a/button.c
+++ b/button.c
@@ -21,7 +21,6 @@
 
 #include "button.h"
 
-#include "common/xutil.h"
 #include "common/tokenize.h"
 
 DO_LUA_TOSTRING(button_t, button, "button")
@@ -59,7 +58,6 @@ luaA_button_gc(lua_State *L)
 static int
 luaA_button_new(lua_State *L)
 {
-    int len;
     xcb_button_t xbutton;
     button_t *button, *orig;
     luaA_ref press = LUA_REFNIL, release = LUA_REFNIL;
@@ -110,16 +108,7 @@ luaA_button_new(lua_State *L)
     button->release = release;
     button->button = xbutton;
 
-    len = lua_objlen(L, 2);
-    for(int i = 1; i <= len; i++)
-    {
-        size_t blen;
-        const char *buf;
-        lua_rawgeti(L, 2, i);
-        buf = luaL_checklstring(L, -1, &blen);
-        button->mod |= xutil_key_mask_fromstr(buf, blen);
-        lua_pop(L, 1);
-    }
+    luaA_setmodifiers(L, 2, &button->mod);
 
     return 1;
 }
diff --git a/key.c b/key.c
index d267adcd..2047e67f 100644
--- a/key.c
+++ b/key.c
@@ -301,7 +301,7 @@ luaA_keystore(keyb_t *key, const char *str, ssize_t len)
 static int
 luaA_key_new(lua_State *L)
 {
-    size_t i, len;
+    size_t len;
     keyb_t *k;
     const char *key;
     luaA_ref press = LUA_REFNIL, release = LUA_REFNIL;
@@ -323,15 +323,7 @@ luaA_key_new(lua_State *L)
     k->press = press;
     k->release = release;
 
-    len = lua_objlen(L, 2);
-    for(i = 1; i <= len; i++)
-    {
-        size_t blen;
-        lua_rawgeti(L, 2, i);
-        key = luaL_checklstring(L, -1, &blen);
-        lua_pop(L, 1);
-        k->mod |= xutil_key_mask_fromstr(key, blen);
-    }
+    luaA_setmodifiers(L, 2, &k->mod);
 
     return 1;
 }
@@ -400,6 +392,25 @@ luaA_pushmodifiers(lua_State *L, uint16_t modifiers)
     return 1;
 }
 
+/** Take a modifier table from the stack and set modifiers in mod.
+ * \param L The Lua VM state.
+ * \param ud The index of the table.
+ * \param mod Where to set the modifiers.
+ */
+void
+luaA_setmodifiers(lua_State *L, int ud, uint16_t *mod)
+{
+    ssize_t len = lua_objlen(L, ud);
+    for(int i = 1; i <= len; i++)
+    {
+        lua_rawgeti(L, ud, i);
+        size_t blen;
+        const char *key = luaL_checklstring(L, -1, &blen);
+        *mod |= xutil_key_mask_fromstr(key, blen);
+        lua_pop(L, 1);
+    }
+}
+
 /** Key object.
  * \param L The Lua VM state.
  * \return The number of elements pushed on stack.
diff --git a/key.h b/key.h
index 48ebecb6..9f4cf2de 100644
--- a/key.h
+++ b/key.h
@@ -57,5 +57,6 @@ int luaA_key_array_get(lua_State *, keybindings_t *);
 
 void window_grabkeys(xcb_window_t, keybindings_t *);
 int luaA_pushmodifiers(lua_State *, uint16_t);
+void luaA_setmodifiers(lua_State *, int, uint16_t *);
 
 #endif