diff --git a/includes/ajaxHandler.class.php b/includes/ajaxHandler.class.php
index a10512e6..9790c37d 100644
--- a/includes/ajaxHandler.class.php
+++ b/includes/ajaxHandler.class.php
@@ -73,12 +73,12 @@ class AjaxHandler
         return true;
     }
 
-    protected function checkEmptySet(string $val) : bool
+    protected static function checkEmptySet(string $val) : bool
     {
         return $val === '';                                 // parameter is expected to be empty
     }
 
-    protected function checkLocale(string $val) : int
+    protected static function checkLocale(string $val) : int
     {
         if (preg_match('/^'.implode('|', array_keys(array_filter(Util::$localeStrings))).'$/', $val))
             return intVal($val);
@@ -86,7 +86,7 @@ class AjaxHandler
         return -1;
     }
 
-    protected function checkInt(string $val) : int
+    protected static function checkInt(string $val) : int
     {
         if (preg_match('/^-?\d+$/', $val))
             return intVal($val);
@@ -94,7 +94,7 @@ class AjaxHandler
         return 0;
     }
 
-    protected function checkIdList(string $val) : array
+    protected static function checkIdList(string $val) : array
     {
         if (preg_match('/^-?\d+(,-?\d+)*$/', $val))
             return array_map('intVal', explode(',', $val));
@@ -102,7 +102,7 @@ class AjaxHandler
         return [];
     }
 
-    protected function checkIdListUnsigned(string $val) : array
+    protected static function checkIdListUnsigned(string $val) : array
     {
         if (preg_match('/\d+(,\d+)*/', $val))
             return array_map('intVal', explode(',', $val));
@@ -110,10 +110,10 @@ class AjaxHandler
         return [];
     }
 
-    protected function checkFulltext(string $val) : string
+    protected static function checkFulltext(string $val) : string
     {
         // trim non-printable chars
-        return preg_replace('/[\p{C}]/ui', '', $val);
+        return preg_replace('/[\p{Cf} \p{Co} \p{Cs} \p{Cn}]/ui', '', $val);
     }
 }
 ?>
diff --git a/includes/ajaxHandler/account.class.php b/includes/ajaxHandler/account.class.php
index 776b2c0a..3b5f85a6 100644
--- a/includes/ajaxHandler/account.class.php
+++ b/includes/ajaxHandler/account.class.php
@@ -165,7 +165,7 @@ class AjaxAccount extends AjaxHandler
             DB::Aowow()->query('DELETE FROM ?_account_favorites WHERE `userId` = ?d AND `type` = ?d AND `typeId` = ?d', User::$id, $type, $typeId);
     }
 
-    protected function checkScale(string $val) : string
+    protected static function checkScale(string $val) : string
     {
         if (preg_match('/^((\w+:\d+)(,\w+:\d+)*)$/', $val))
             return $val;
@@ -173,7 +173,7 @@ class AjaxAccount extends AjaxHandler
         return '';
     }
 
-    protected function checkName(string $val) : string
+    protected static function checkName(string $val) : string
     {
         $var = trim(urldecode($val));
 
diff --git a/includes/ajaxHandler/admin.class.php b/includes/ajaxHandler/admin.class.php
index 5e26a1b3..f8996c21 100644
--- a/includes/ajaxHandler/admin.class.php
+++ b/includes/ajaxHandler/admin.class.php
@@ -467,7 +467,7 @@ class AjaxAdmin extends AjaxHandler
         return '-1';
     }
 
-    protected function checkKey(string $val) : string
+    protected static function checkKey(string $val) : string
     {
         // expecting string
         if (preg_match('/[^a-z0-9_\.\-]/i', $val))
@@ -476,7 +476,7 @@ class AjaxAdmin extends AjaxHandler
         return strtolower($val);
     }
 
-    protected function checkUser($val) : string
+    protected static function checkUser($val) : string
     {
         $n = Util::lower(trim(urldecode($val)));
 
@@ -486,7 +486,7 @@ class AjaxAdmin extends AjaxHandler
         return '';
     }
 
-    protected function checkScale($val) : string
+    protected static function checkScale($val) : string
     {
         if (preg_match('/^((\w+:\d+)(,\w+:\d+)*)$/', $val))
             return $val;
@@ -494,7 +494,7 @@ class AjaxAdmin extends AjaxHandler
         return '';
     }
 
-    private function confOnChange(string $key, string $val, string &$msg) : bool
+    private static function confOnChange(string $key, string $val, string &$msg) : bool
     {
         $fn = $buildList = null;
 
diff --git a/includes/ajaxHandler/comment.class.php b/includes/ajaxHandler/comment.class.php
index 4c73cd65..ea046e08 100644
--- a/includes/ajaxHandler/comment.class.php
+++ b/includes/ajaxHandler/comment.class.php
@@ -92,7 +92,7 @@ class AjaxComment extends AjaxHandler
 
         // trim to max length
         if (!User::isInGroup(U_GROUP_MODERATOR) && mb_strlen($this->_post['commentbody']) > (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)))
-            $this->post['commentbody'] = mb_substr($this->_post['commentbody'], 0, (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)));
+            $this->_post['commentbody'] = mb_substr($this->_post['commentbody'], 0, (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)));
 
         if (User::canComment())
         {
@@ -144,7 +144,7 @@ class AjaxComment extends AjaxHandler
 
         // trim to max length
         if (!User::isInGroup(U_GROUP_MODERATOR) && mb_strlen($this->_post['body']) > (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)))
-            $this->post['body'] = mb_substr($this->_post['body'], 0, (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)));
+            $this->_post['body'] = mb_substr($this->_post['body'], 0, (self::COMMENT_LENGTH_MAX * (User::isPremium() ? 3 : 1)));
 
         $update = array(
             'body'       => $this->_post['body'],
diff --git a/includes/ajaxHandler/data.class.php b/includes/ajaxHandler/data.class.php
index 644d3b39..2df14239 100644
--- a/includes/ajaxHandler/data.class.php
+++ b/includes/ajaxHandler/data.class.php
@@ -117,12 +117,12 @@ class AjaxData extends AjaxHandler
         return $result;
     }
 
-    protected function checkSkill(string $val) : array
+    protected static function checkSkill(string $val) : array
     {
         return array_intersect([171, 164, 333, 202, 182, 773, 755, 165, 186, 393, 197, 185, 129, 356], explode(',', $val));
     }
 
-    protected function checkCallback(string $val) : bool
+    protected static function checkCallback(string $val) : bool
     {
         return substr($val, 0, 29) === '$WowheadProfiler.loadOnDemand';
     }
diff --git a/includes/ajaxHandler/profile.class.php b/includes/ajaxHandler/profile.class.php
index ba7eb65c..7bb61aa1 100644
--- a/includes/ajaxHandler/profile.class.php
+++ b/includes/ajaxHandler/profile.class.php
@@ -746,7 +746,7 @@ class AjaxProfile extends AjaxHandler
     */
     protected function handlePurge() : void { }             // removes completion data (as uploaded by the wowhead client) Just fail silently if someone triggers this manually
 
-    protected function checkItemList($val) : array
+    protected static function checkItemList($val) : array
     {
         // expecting item-list
         if (preg_match('/\d+(:\d+)*/', $val))
@@ -755,7 +755,7 @@ class AjaxProfile extends AjaxHandler
         return [];
     }
 
-    protected function checkUser(string $val) : string
+    protected static function checkUser(string $val) : string
     {
         if (User::isValidName($val))
             return $val;