diff --git a/attachments/pages/index.html b/attachments/pages/index.html
index 89485159..fb5426c9 100644
--- a/attachments/pages/index.html
+++ b/attachments/pages/index.html
@@ -69,6 +69,7 @@
   
   <script type='text/mustache' class="columnActionsTemplate">
     <li><a data-action="bulkEdit" class="menuAction" href="JavaScript:void(0);">Transform...</a></li>
+    <li><a data-action="deleteColumn" class="menuAction" href="JavaScript:void(0);">Delete this column</a></li>
   </script>
 
   <script type='text/mustache' class="titleTemplate"><span id="project-name-button" class="app-path-section">{{db_name}}</span></script>
diff --git a/attachments/script/costco.js b/attachments/script/costco.js
index 1ca8dd4a..dcc7c478 100644
--- a/attachments/script/costco.js
+++ b/attachments/script/costco.js
@@ -3,60 +3,117 @@
 var costco = function() {
 
   function handleEditorChange(e) {
-    mapDocs(app.cache, e.target.value, true);
-  }
-
-  function mapDocs(docs, funcString, preview) {
-    if(preview) var errors = $('.expression-preview-parsing-status');
-    try {
-      eval("var editFunc = " + funcString);
-      if(preview) errors.text('No syntax error.');
-    } catch(e) {
-      if(preview) errors.text(e+"");
+    var editFunc = evalFunction(e.target.value);
+    var errors = $('.expression-preview-parsing-status');
+    if (_.isFunction(editFunc)) {
+      errors.text('No syntax error.');
+    } else {
+      errors.text(editFunc);
       return;
     }
+    previewTransform(app.cache, editFunc);
+  }
+  
+  function evalFunction(funcString) {
+    try {
+      eval("var editFunc = " + funcString);
+      return editFunc;
+    } catch(e) {
+      return e+"";
+    }
+  }
+  
+  function previewTransform(docs, editFunc) {
+    var preview = [];
+    var updated = mapDocs(docs, editFunc);
+    for (var i = 0; i < updated.docs.length; i++) {      
+      var before = docs[i]
+        , after = updated.docs[i]
+        ;
+      if (!after) after = {};
+      preview.push({before: JSON.stringify(before[app.currentColumn]), after: JSON.stringify(after[app.currentColumn])});      
+    }
+    util.render('editPreview', 'expression-preview-container', {rows: preview});
+  }
 
-    var toUpdate = []
-      , deleted = 0
-      , edited = 0
-      , failed = 0
+  function mapDocs(docs, editFunc) {
+    var edited = []
+      , deleted = []
+      , failed = []
       ;
     
-    if(preview) var preview = [];
-      
-    _.each(docs, function(doc) {
+    var updatedDocs = _.map(docs, function(doc) {
       try {
         var updated = editFunc(_.clone(doc));
       } catch(e) {
-        failed++; // ignore if it throws on this doc
+        failed.push(doc);
         return;
       }
       if(updated === null) {
-        doc._deleted = true;
-        toUpdate.push(doc);
-        deleted++;
+        updated = {_deleted: true};
+        edited.push(updated);
+        deleted.push(doc);
       }
       else if(updated && !_.isEqual(updated, doc)) {
-        toUpdate.push(updated);
-        edited++;
+        edited.push(updated);
       }
-      
-      if(preview) preview.push({before: JSON.stringify(doc[app.currentColumn]), after: JSON.stringify(updated[app.currentColumn])});
+      return updated;      
     });
     
-    if(preview) util.render('editPreview', 'expression-preview-container', {rows: preview});
-    return toUpdate;
+    return {
+      edited: edited, 
+      docs: updatedDocs, 
+      deleted: deleted, 
+      failed: failed
+    };
+  }
+  
+  function updateDocs(editFunc) {
+    var dfd = $.Deferred();
+    util.notify("Updating documents...", {persist: true, loader: true});
+    couch.request({url: app.baseURL + "api/json"}).then(function(docs) {
+      var toUpdate = costco.mapDocs(docs.docs, editFunc).edited;
+      costco.uploadDocs(toUpdate).then(
+        function(updatedDocs) { 
+          util.notify(updatedDocs.length + " documents updated successfully");
+          recline.fetchRows(false, app.offset);
+          dfd.resolve(updatedDocs);
+        },
+        function(err) {
+          util.notify("Errorz! " + err);
+          dfd.reject(err);
+        }
+      );
+    });
+    return dfd.promise();
   }
 
-  function updateDocs(docs, callback) {
-    if(!docs.length)
-      return callback("Failed to update");    
-    couch.request({url: app.baseURL + "api/_bulk_docs", type: "POST", data: JSON.stringify({docs: docs})}).then(callback);
+  function uploadDocs(docs) {
+    var dfd = $.Deferred();
+    if(!docs.length) dfd.resolve("Failed to update");
+    couch.request({url: app.baseURL + "api/_bulk_docs", type: "POST", data: JSON.stringify({docs: docs})})
+      .then(
+        dfd.resolve, 
+        function(err) { dfd.reject(err.responseText) }
+      );
+    return dfd.promise();
+  }
+  
+  function deleteColumn(name) {
+    var deleteFunc = function(doc) {
+      delete doc[name];
+      return doc;
+    }
+    return updateDocs(deleteFunc);
   }
 
   return {
     handleEditorChange: handleEditorChange,
+    evalFunction: evalFunction,
+    previewTransform: previewTransform,
     mapDocs: mapDocs,
-    updateDocs: updateDocs
+    updateDocs: updateDocs,
+    uploadDocs: uploadDocs,
+    deleteColumn: deleteColumn
   };
 }();
\ No newline at end of file
diff --git a/attachments/script/recline.js b/attachments/script/recline.js
index 59630985..aefbae01 100644
--- a/attachments/script/recline.js
+++ b/attachments/script/recline.js
@@ -23,7 +23,12 @@ var recline = function() {
         json: function() { window.location.href = "_rewrite/api/json" },
         urlImport: function() { showDialog('urlImport') },
         pasteImport: function() { showDialog('pasteImport') },
-        uploadImport: function() { showDialog('uploadImport') }
+        uploadImport: function() { showDialog('uploadImport') },
+        deleteColumn: function() {
+          var msg = "Are you sure? This will delete '" + app.currentColumn + "' from all documents.";
+          if (confirm(msg)) costco.deleteColumn(app.currentColumn);
+          util.hide('menu');
+        }
       }
       
       actions[$(e.target).attr('data-action')]();
diff --git a/attachments/script/site.js b/attachments/script/site.js
index d2f639a7..87309771 100644
--- a/attachments/script/site.js
+++ b/attachments/script/site.js
@@ -113,15 +113,13 @@ app.after = {
     
     $('.dialog-content .okButton').click(function(e) {
       var funcText = $('.expression-preview-code').val();
+      var editFunc = costco.evalFunction(funcText);
+      if (!_.isFunction(editFunc)) {
+        util.notify("Error with function! " + editFunc);
+        return;
+      }
       util.hide('dialog');
-      util.notify("Updating documents...", {persist: true, loader: true});
-      couch.request({url: app.baseURL + "api/json"}).then(function(docs) {
-        var toUpdate = costco.mapDocs(docs.docs, funcText);
-        costco.updateDocs(toUpdate, function(msg) { 
-          util.notify(msg.length + " documents updated successfully");
-          recline.fetchRows(false, app.offset);
-        });
-      });
+      costco.updateDocs(editFunc);
     })
     
     var editor = $('.expression-preview-code');
@@ -160,5 +158,6 @@ app.sammy = $.sammy(function () {
 });
 
 $(function() {
+  util.traverse = require('traverse');
   app.sammy.run();  
 })
\ No newline at end of file