diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index b0a50d0f..027a9b43 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -652,19 +652,6 @@ namespace WebSocketSharp
       return value > 0 && value < 65536;
     }
 
-    internal static bool IsPrintable (this string value)
-    {
-      foreach (var c in value) {
-        if (c < 0x20)
-          return false;
-
-        if (c > 0x7e)
-          return false;
-      }
-
-      return true;
-    }
-
     internal static bool IsReserved (this ushort code)
     {
       return code == 1004