To be honest I disagree with the way we do sanitizing here and would …

metrics-graphite/src/main/java/com/codahale/metrics/graphite/GraphiteSanitize.java

@@ -1,26 +1,32 @@
 package com.codahale.metrics.graphite;
 
 class GraphiteSanitize {
+
+    private static final String ACCEPTED_CHARS = ".-_";
+
     /** Replaces all characters from a given string that are not ascii and not alphanumeric
      *  with a dash */
-    static String sanitize(String string, char replacement) {
-        String replaced = replaceFrom(string, replacement);
+    static String sanitize(String string, char replacementCh) {
+        String replaced = replaceFrom(string, replacementCh);
+
+        final String replacementStr = String.valueOf(replacementCh);
+        final String duplicateChars = (replacementStr+replacementStr);
 
         // Consolidate multiple dashes into a single one
-        String result = replaced.replace("--", "-");
+        String result = replaced.replace(duplicateChars, replacementStr);
         while (!result.equals(replaced)) {
             replaced = result;
-            result = replaced.replace("--", "-");
+            result = replaced.replace(duplicateChars, replacementStr);
         }
 
         // Remove any leading or trailing dashes
-        return strip(result, replacement);
+        return strip(result, replacementCh);
     }
 
     /** A char matches when it is a letter or digit and it is ASCII, in Guava terminology,
      *  this would be CharMatcher.ASCII.and(CharMatcher.JAVA_LETTER_OR_DIGIT).negate() */
     private static boolean matches(char c) {
-        return !(Character.isLetterOrDigit(c) && c <= '\u007f');
+        return !((Character.isLetterOrDigit(c) || ACCEPTED_CHARS.contains(String.valueOf(c))) && c <= '\u007f');
     }
 
     /** Replace all characters that we're interested in with a replacement character,

metrics-graphite/src/test/java/com/codahale/metrics/graphite/GraphiteSanitizeTest.java

@@ -15,12 +15,15 @@ public void sanitizeGraphiteValues() {
         softly.assertThat(GraphiteSanitize.sanitize("  Foo Bar  ", '-')).isEqualTo("Foo-Bar");
         softly.assertThat(GraphiteSanitize.sanitize("Foo@Bar", '-')).isEqualTo("Foo-Bar");
         softly.assertThat(GraphiteSanitize.sanitize("Foó Bar", '-')).isEqualTo("Fo-Bar");
-        softly.assertThat(GraphiteSanitize.sanitize("||ó/.", '-')).isEqualTo("");
+        softly.assertThat(GraphiteSanitize.sanitize("||ó/.", '-')).isEqualTo(".");
         softly.assertThat(GraphiteSanitize.sanitize("${Foo:Bar:baz}", '-')).isEqualTo("Foo-Bar-baz");
-        softly.assertThat(GraphiteSanitize.sanitize("St. Foo's of Bar", '-')).isEqualTo("St-Foo-s-of-Bar");
+        softly.assertThat(GraphiteSanitize.sanitize("St. Foo's of Bar", '-')).isEqualTo("St.-Foo-s-of-Bar");
         softly.assertThat(GraphiteSanitize.sanitize("(Foo and (Bar and (Baz)))", '-')).isEqualTo("Foo-and-Bar-and-Baz");
-        softly.assertThat(GraphiteSanitize.sanitize("Foo.bar.baz", '-')).isEqualTo("Foo-bar-baz");
+        softly.assertThat(GraphiteSanitize.sanitize("Foo.bar.baz", '-')).isEqualTo("Foo.bar.baz");
         softly.assertThat(GraphiteSanitize.sanitize("FooBar", '-')).isEqualTo("FooBar");
+        softly.assertThat(GraphiteSanitize.sanitize("##)", '-')).isEqualTo("");
+        softly.assertThat(GraphiteSanitize.sanitize("search_total)", '-')).isEqualTo("search_total");
+        softly.assertThat(GraphiteSanitize.sanitize("search-error)", '-')).isEqualTo("search-error");
 
         softly.assertAll();
     }