diff --git a/library/HTMLPurifier/Injector/RemoveSpansWithoutAttributes.php b/library/HTMLPurifier/Injector/RemoveSpansWithoutAttributes.php
index 42d514447..822ba7bda 100644
--- a/library/HTMLPurifier/Injector/RemoveSpansWithoutAttributes.php
+++ b/library/HTMLPurifier/Injector/RemoveSpansWithoutAttributes.php
@@ -74,7 +74,7 @@ public function handleElement(&$token)
 
         if ($current instanceof HTMLPurifier_Token_End && $current->name === 'span') {
             // Mark closing span tag for deletion
-            $this->markForDeletion->attach($current);
+            $this->markForDeletion->offsetSet($current);
             // Delete open span tag
             $token = false;
         }
@@ -85,8 +85,8 @@ public function handleElement(&$token)
      */
     public function handleEnd(&$token)
     {
-        if ($this->markForDeletion->contains($token)) {
-            $this->markForDeletion->detach($token);
+        if ($this->markForDeletion->offsetExists($token)) {
+            $this->markForDeletion->offsetUnset($token);
             $token = false;
         }
     }
diff --git a/library/HTMLPurifier/URISchemeRegistry.php b/library/HTMLPurifier/URISchemeRegistry.php
index 4ac8a0b76..7dcaf9ab6 100644
--- a/library/HTMLPurifier/URISchemeRegistry.php
+++ b/library/HTMLPurifier/URISchemeRegistry.php
@@ -44,6 +44,10 @@ public function getScheme($scheme, $config, $context)
             $config = HTMLPurifier_Config::createDefault();
         }
 
+        if ($scheme === null) {
+            return;
+        }
+
         // important, otherwise attacker could include arbitrary file
         $allowed_schemes = $config->get('URI.AllowedSchemes');
         if (!$config->get('URI.OverrideAllowedSchemes') &&