diff --git a/README.md b/README.md
index fa60660..724708d 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,7 @@ But sometimes you need to add stuff dynamically
 
 ### Kepi
 
-#### constructor(data, options)
+#### constructor(data, customOptions)
  data can be
   - null
   - an Object (see example).  In may cases this is all you really need.
@@ -103,10 +103,10 @@ Sets all headers in options.SAFE or options.safe, creating if needed.
 
 #### add(data)
 Adds data to the header value
-  - `List.add(...items)` for convenience, accepts an array, **or** one or more individual items
+  - `List.add(...items)`
     - _e.g._ `add('a','b')` is equivalent to `add(['a','b'])`
   - `Policies.add(policyName, ...items)` requires a policy name first
-    - `...items` may be an array, **or** one or more individual items
+  - **note** items will be flattened one level deep, so `add('a','b')` is equivalent to `add(['a','b'])`
 
 #### applyTo(response)
 Write the header to the response.  You will seldom call this directly.
@@ -123,7 +123,7 @@ Set the header to a "safe" value, as provided in the options.
 
 #### set(value)
 Sets the value
-  - `List.set(...items)` like add(), this accepts an array, or one or more individual items
+  - `List.set(...items)` like add(), items will be flattened
 
 
 ## Customization
@@ -131,7 +131,12 @@ Sets the value
 You can customize or add to behavior by passing a customOptions parameter to the Kepi function.
 This will get `Object.assign`ed onto the default settings in defaults.js.
 
-Since `Object.assign` is shallow, and making a deep copy is a bit of a pain, instead, provide user options in the **lowercase**
+#### Simple Options
+  - setupNicknames (default = true) controls if nicknames are setup
+  - resetAfterApply (default = false) will reset to initial data after calling applyTo()
+
+#### Complex Options
+Since `Object.assign` is shallow, and making a deep copy is a bit of a pain, instead, provide complex user options in the **lowercase**
 properties given at the end of defaults.js.
 
  - headerClasses allows you to add or override the class for a Header
diff --git a/header.js b/header.js
index a93ed8b..a47cb92 100644
--- a/header.js
+++ b/header.js
@@ -141,7 +141,7 @@ class Policies extends Header {
   }
 
   add(policyName, ...items) {
-    items = expandFirstArgIfArray(items);
+    items = flatten1(items);
     let policyValues = this.data[policyName];
     if (policyValues)
       policyValues.push(...items);
@@ -195,12 +195,12 @@ class List extends Header {
   }
 
   add(...items) {
-    this.data.push(...expandFirstArgIfArray(items));
+    this.data.push(...flatten1(items));
     return this;
   }
 
   set(...items) {
-    this.data = [...expandFirstArgIfArray(items)];
+    this.data = [...flatten1(items)];
     return this;
   }
 
@@ -215,8 +215,9 @@ function forceArray(x) {
     return x ? [x] : [];
 }
 
-function expandFirstArgIfArray(rest) {
-  return (rest.length === 1) && Array.isArray(rest[0]) ? rest[0] : rest;
+// 1 level deep flatten
+function flatten1(arr) {
+  return [].concat(...arr);
 }
 
 module.exports = { Header };
diff --git a/kepi.js b/kepi.js
index 82bcb13..ec0350d 100644
--- a/kepi.js
+++ b/kepi.js
@@ -5,26 +5,28 @@ const Header = require('./header').Header;
 class Kepi {
 
   constructor(data, customOptions) {
+    data = data || {};
     this.options = Object.assign({}, DEFAULTS, customOptions);
-    this.headers = {};
+    this.resetData = this.options.resetAfterApply ? data : null;
 
     if (this.options.setupNicknames) {
       this._setupNicknames(this.options.NICKNAMES);
       this._setupNicknames(this.options.nicknames);
     }
 
-    if (data === 'safe')
-      this.safe();
-    else
-      this._setInitialData(data || {});
+    this._setData(data);
   }
 
 
+
   applyTo(response) {
     let headerNames = Object.keys(this.headers);
     headerNames.forEach( (headerName) => {
       this.headers[headerName].applyTo(response);
-    });   
+    });
+    if (this.resetData)
+      this._setData(this.resetData);
+
     return this;
   }
 
@@ -69,12 +71,18 @@ class Kepi {
   }
 
 
-  _setInitialData(data) {
+  _setData(data) {
+    this.headers = {};
+
+    if (data === 'safe')
+      return this.safe();
+
     let headerNames = Object.keys(data);
     headerNames.forEach( (headerName) => {
       let fullName = this._fullName(headerName);
       this.headers[headerName] = Header.create(this._headerType(fullName), fullName, data[headerName], this.options);
     });
+    return this;
   }
 
 
diff --git a/test/test.js b/test/test.js
index a0fca10..33a03b6 100644
--- a/test/test.js
+++ b/test/test.js
@@ -118,14 +118,17 @@ test('delete', function(t) {
 })
 
 const CLEAR_AND_ADD = '{"stringHeader":"addedstring","listHeader":"a, b, c","directiveHeader1":"foo1 newValue1 newValue2","directiveHeader2":"bar2 originalbarValue2; foo3 newfoovalue3"}';
+const CLEAR_AND_ADD_AFTER_RESET = '{"stringHeader":"originalstring","listHeader":"1, 2, 3","directiveHeader1":"foo1 originalfooValue1; bar1 originalbarValue1","directiveHeader2":"foo2 originalfooValue2; bar2 originalbarValue2"}';
 
-test('clear & add', function(t) {
+test('clear & add & reset', function(t) {
   let kepi = Kepi({
     stringHeader: 'originalstring',
     listHeader: [1,2,3],
     directiveHeader1: { foo1: 'originalfooValue1', bar1: 'originalbarValue1'},
     directiveHeader2: { foo2: 'originalfooValue2', bar2: 'originalbarValue2'}
-  });
+  },
+  { resetAfterApply: true }
+  );
   let res = mockResponse();
 
   kepi.header('stringHeader').clear().add('addedstring');
@@ -135,6 +138,11 @@ test('clear & add', function(t) {
 
   kepi.applyTo(res);
   t.equals(res.toString(), CLEAR_AND_ADD);
+
+  res = mockResponse();
+  kepi.applyTo(res);
+  t.equals(res.toString(), CLEAR_AND_ADD_AFTER_RESET);
+
   t.end();
 })