diff --git a/min/lib/Minify/CSS/UriRewriter.php b/min/lib/Minify/CSS/UriRewriter.php
index 43cc254..e963fb8 100644
--- a/min/lib/Minify/CSS/UriRewriter.php
+++ b/min/lib/Minify/CSS/UriRewriter.php
@@ -66,16 +66,20 @@ class Minify_CSS_UriRewriter {
         self::$debugText .= "\n";
         
         $css = self::_trimUrls($css);
-        
+
+        $css = self::_owlifySvgPaths($css);
+
         // rewrite
         $css = preg_replace_callback('/@import\\s+([\'"])(.*?)[\'"]/'
             ,array(self::$className, '_processUriCB'), $css);
         $css = preg_replace_callback('/url\\(\\s*([\'"](.*?)[\'"]|[^\\)\\s]+)\\s*\\)/'
             ,array(self::$className, '_processUriCB'), $css);
 
+        $css = self::_unOwlify($css);
+
         return $css;
     }
-    
+
     /**
      * In CSS content, prepend a path to relative URIs
      * 
@@ -90,6 +94,8 @@ class Minify_CSS_UriRewriter {
         self::$_prependPath = $path;
         
         $css = self::_trimUrls($css);
+
+        $css = self::_owlifySvgPaths($css);
         
         // append
         $css = preg_replace_callback('/@import\\s+([\'"])(.*?)[\'"]/'
@@ -97,6 +103,8 @@ class Minify_CSS_UriRewriter {
         $css = preg_replace_callback('/url\\(\\s*([\'"](.*?)[\'"]|[^\\)\\s]+)\\s*\\)/'
             ,array(self::$className, '_processUriCB'), $css);
 
+        $css = self::_unOwlify($css);
+
         self::$_prependPath = null;
         return $css;
     }
@@ -304,4 +312,30 @@ class Minify_CSS_UriRewriter {
             ? "@import {$quoteChar}{$uri}{$quoteChar}"
             : "url({$quoteChar}{$uri}{$quoteChar})";
     }
+
+    /**
+     * Mungs some inline SVG URL declarations so they won't be touched
+     *
+     * @link https://github.com/mrclay/minify/issues/517
+     * @see _unOwlify
+     *
+     * @param string $css
+     * @return string
+     */
+    private static function _owlifySvgPaths($css) {
+        return preg_replace('~\b((?:clip-path|mask|-webkit-mask)\s*\:\s*)url(\(\s*#\w+\s*\))~', '$1owl$2', $css);
+
+    }
+
+    /**
+     * Undo work of _owlify
+     *
+     * @see _owlifySvgPaths
+     *
+     * @param string $css
+     * @return string
+     */
+    private static function _unOwlify($css) {
+        return preg_replace('~\b((?:clip-path|mask|-webkit-mask)\s*\:\s*)owl~', '$1url', $css);
+    }
 }
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp.css b/min_unit_tests/_test_files/css_uriRewriter/exp.css
index 22c109f..3296c26 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp.css
@@ -8,6 +8,10 @@
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
 @import url(foo:bar); /* scheme, should not alter */
+foo {clip-path:url(#c1)} /* inline clip path, should not alter */
+foo {clip-path:url(/_test_files/css_uriRewriter/foo.svg#c1)}
+foo {mask: url(#c1)} /* should not alter */
+foo {-webkit-mask: url(#c1)} /* should not alter */
 foo {background:url('/_test_files/css_uriRewriter/bar/foo.png')}
 foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
index ce31df1..bc09c44 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend.css
@@ -8,6 +8,10 @@
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
 @import url(foo:bar); /* scheme, should not alter */
+foo {clip-path:url(#c1)} /* inline clip path, should not alter */
+foo {clip-path:url(http://cnd.com/A/B/foo.svg#c1)}
+foo {mask: url(#c1)} /* should not alter */
+foo {-webkit-mask: url(#c1)} /* should not alter */
 foo {background:url('http://cnd.com/A/B/bar/foo.png')}
 foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
index 087d94d..c8f7c61 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/exp_prepend2.css
@@ -8,6 +8,10 @@
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
 @import url(foo:bar); /* scheme, should not alter */
+foo {clip-path:url(#c1)} /* inline clip path, should not alter */
+foo {clip-path:url(//cnd.com/A/B/foo.svg#c1)}
+foo {mask: url(#c1)} /* should not alter */
+foo {-webkit-mask: url(#c1)} /* should not alter */
 foo {background:url('//cnd.com/A/B/bar/foo.png')}
 foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */
diff --git a/min_unit_tests/_test_files/css_uriRewriter/in.css b/min_unit_tests/_test_files/css_uriRewriter/in.css
index 3bdce36..0200450 100644
--- a/min_unit_tests/_test_files/css_uriRewriter/in.css
+++ b/min_unit_tests/_test_files/css_uriRewriter/in.css
@@ -8,6 +8,10 @@
 @import url("/css/foo.css"); /* abs, should not alter */
 @import url(/css2/foo.css); /* abs, should not alter */
 @import url(foo:bar); /* scheme, should not alter */
+foo {clip-path:url(#c1)} /* inline clip path, should not alter */
+foo {clip-path:url(foo.svg#c1)}
+foo {mask: url( #c1 )} /* should not alter */
+foo {-webkit-mask: url( #c1 )} /* should not alter */
 foo {background:url('bar/foo.png')}
 foo {background:url('http://foo.com/css/foo.css');} /* scheme, should not alter */
 foo {background:url("//foo.com/css/foo.css");} /* protocol relative, should not alter */