diff --git a/NEWS.md b/NEWS.md
index 29626c1b..286c78f1 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -5,6 +5,7 @@
  * Include version in GET /style response
  * Support version and convert parameters in POST /style request
  * Autodetect target mapnik version and let config override it
+ * Add tools/reset_styles script to batch-reset (and optionally convert) styles
 * Configurable logging format (#4)
 * Detailed error on missing user metadata 
 * Properly handle unauthenticated requests for metadata
diff --git a/tools/reset_styles b/tools/reset_styles
index 53b736dc..863312ef 100755
--- a/tools/reset_styles
+++ b/tools/reset_styles
@@ -1,35 +1,85 @@
 #!/usr/bin/env node
 
-// Reset redis-stored XML styles so that they are regenerated
-// from CartoCSS on next tile request
+var path = require('path');
 
-var redis = require('redis')
+// Reset all styles in the store
+var grainstore = require('../node_modules/grainstore/lib/grainstore');
+var mapnik = require('mapnik');
+var redis = require('redis');
 
-var REDIS_PORT = 6379; // TODO: make a parameter
+function usage(me, exitcode) {
+  console.log("Usage: " + me + " [--convert] [<target_mapnik_version>]");
+  process.exit(exitcode);
+}
+
+var doConvert = false;
+var MAPNIK_VERSION;
+
+var node_path = process.argv.shift(); 
+var script_path = process.argv.shift(); 
+var me = path.basename(script_path);
+var arg;
+while ( arg = process.argv.shift() ) {
+  if ( arg == '--convert' ) {
+    doConvert = true;
+  } else if ( ! MAPNIK_VERSION ) {
+    MAPNIK_VERSION = arg;
+  }
+  else {
+    usage(me, 1);
+  }
+}
+
+if ( ! MAPNIK_VERSION ) {
+  MAPNIK_VERSION = mapnik.versions.mapnik;
+}
+
+console.log( (doConvert ? "Converting" : "Resetting" ) + ' all styles to target ' + MAPNIK_VERSION);
+
+var REDIS_PORT = 6379; // TODO: make a command line parameter
 
 var dbnum = 0;
 
+var mml_store = new grainstore.MMLStore({port:REDIS_PORT}, {mapnik_version:MAPNIK_VERSION});
+
+var failures = [];
+
 var client = redis.createClient(REDIS_PORT, 'localhost');
 client.on('connect', function() {
   client.select(dbnum);
   client.keys('map_style|*', function(err, matches) {
 
     processNext = function() {
-      if ( ! matches.length ) process.exit(0);
+      if ( ! matches.length ) process.exit(failures.length);
       var k = matches.shift();
-      console.log("Resetting XML in key: " + k);
-      client.get(k, function(err, val) {
-        if ( err ) throw err;
-        val = JSON.parse(val);
-        delete val.xml;
-        client.set(k, JSON.stringify(val), function() {
-          console.log("done with style " + k);
-          processNext();
-        });
+
+      if ( /map_style\|.*\|.*\|/.test(k) ) {
+        //console.warn("Key " + k + " is EXTENDED, skipping");
+        processNext();
+      } 
+
+      var params = RegExp(/map_style\|(.*)\|(.*)/).exec(k);
+      var db = params[1];
+      var tab = params[2];
+      var out = 'map_style|' + db + '|' + tab + ': ';
+
+      var mml_builder = mml_store.mml_builder({dbname:db, table:tab},
+                                              function(err, payload) {
+
+          if ( err ) { console.warn(out + err.message); failures.push(k); processNext(); }
+          else {
+            mml_builder.resetStyle(function(err, data) {
+              if ( err ) { console.warn(out + err.message); failures.push(k); }
+              else console.log(out + 'OK' + ( doConvert ? ' (converted)' : '' ));
+              processNext();
+            }, doConvert);
+          }
       });
-    }
+
+    };
 
     processNext();
 
   });
+
 });