diff --git a/phpBB/phpbb/captcha/plugins/captcha_abstract.php b/phpBB/phpbb/captcha/plugins/captcha_abstract.php
index fb8ccc5a70..c6978a1bf1 100644
--- a/phpBB/phpbb/captcha/plugins/captcha_abstract.php
+++ b/phpBB/phpbb/captcha/plugins/captcha_abstract.php
@@ -179,11 +179,6 @@ abstract class captcha_abstract
 		$db->sql_freeresult($result);
 	}
 
-	function uninstall()
-	{
-		$this->garbage_collect(0);
-	}
-
 	function validate()
 	{
 		global $user;
diff --git a/phpBB/phpbb/captcha/plugins/qa.php b/phpBB/phpbb/captcha/plugins/qa.php
index ffc67a7706..3e48df00b2 100644
--- a/phpBB/phpbb/captcha/plugins/qa.php
+++ b/phpBB/phpbb/captcha/plugins/qa.php
@@ -323,14 +323,6 @@ class qa
 		$db->sql_freeresult($result);
 	}
 
-	/**
-	*  API function - we don't drop the tables here, as that would cause the loss of all entered questions.
-	*/
-	function uninstall()
-	{
-		$this->garbage_collect(0);
-	}
-
 	/**
 	*  API function - see what has to be done to validate
 	*/
diff --git a/phpBB/phpbb/captcha/plugins/recaptcha.php b/phpBB/phpbb/captcha/plugins/recaptcha.php
index a5dcf4efc6..1c080ba67b 100644
--- a/phpBB/phpbb/captcha/plugins/recaptcha.php
+++ b/phpBB/phpbb/captcha/plugins/recaptcha.php
@@ -179,11 +179,6 @@ class recaptcha extends captcha_abstract
 		return $hidden_fields;
 	}
 
-	function uninstall()
-	{
-		$this->garbage_collect(0);
-	}
-
 	function validate()
 	{
 		if (!parent::validate())