Remove Unwanted Words from List

I would like to remove unwanted words from this project I am working on. I figured out I can use the Remove Documents Operator to get rid of "http" from my results. I have more words I would like to filter out. For example, "chart", "twitter", "trade", "message" etc. Can someone explain how I can expand the list of words to filter out. I would like to have the flexibility to make changes to the list as needed based on the search results. Also is the Stem Operator required for what I am doing here?

Thanks
Ron McEwan

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.0">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.0.11" expanded="true" name="Process">
    <process expanded="true" height="251" width="413">
      <operator activated="true" class="web:read_rss" compatibility="5.0.4" expanded="true" height="60" name="Read RSS Feed" width="90" x="45" y="30">
        <parameter key="url" value="http://stocktwits.com/streams/all?rss=true"/>
      </operator>
      <operator activated="true" class="text:process_document_from_data" compatibility="5.0.7" expanded="true" height="76" name="Process Documents from Data" width="90" x="45" y="165">
        <parameter key="add_meta_information" value="false"/>
        <parameter key="keep_text" value="true"/>
        <parameter key="prune_method" value="absolute"/>
        <parameter key="prune_below_absolute" value="2"/>
        <parameter key="prune_above_absolute" value="999"/>
        <list key="specify_weights"/>
        <process expanded="true" height="408" width="570">
          <operator activated="true" class="text:remove_document_parts" compatibility="5.0.7" expanded="true" height="60" name="Remove Document Parts" width="90" x="45" y="30">
            <parameter key="deletion_regex" value="http"/>
          </operator>
          <operator activated="true" class="text:tokenize" compatibility="5.0.7" expanded="true" height="60" name="Tokenize" width="90" x="45" y="165"/>
          <operator activated="true" class="text:transform_cases" compatibility="5.0.7" expanded="true" height="60" name="Transform Cases" width="90" x="179" y="165"/>
          <operator activated="true" class="text:filter_by_length" compatibility="5.0.7" expanded="true" height="60" name="Filter Tokens (by Length)" width="90" x="313" y="165">
            <parameter key="max_chars" value="10"/>
          </operator>
          <operator activated="true" class="text:stem_snowball" compatibility="5.0.7" expanded="true" height="60" name="Stem (Snowball)" width="90" x="45" y="300"/>
          <operator activated="true" class="text:filter_stopwords_english" compatibility="5.0.7" expanded="true" height="60" name="Filter Stopwords (English)" width="90" x="179" y="300"/>
          <operator activated="true" class="text:generate_n_grams_terms" compatibility="5.0.7" expanded="true" height="60" name="Generate n-Grams (Terms)" width="90" x="313" y="300">
            <parameter key="max_length" value="3"/>
          </operator>
          <connect from_port="document" to_op="Remove Document Parts" to_port="document"/>
          <connect from_op="Remove Document Parts" from_port="document" to_op="Tokenize" to_port="document"/>
          <connect from_op="Tokenize" from_port="document" to_op="Transform Cases" to_port="document"/>
          <connect from_op="Transform Cases" from_port="document" to_op="Filter Tokens (by Length)" to_port="document"/>
          <connect from_op="Filter Tokens (by Length)" from_port="document" to_op="Stem (Snowball)" to_port="document"/>
          <connect from_op="Stem (Snowball)" from_port="document" to_op="Filter Stopwords (English)" to_port="document"/>
          <connect from_op="Filter Stopwords (English)" from_port="document" to_op="Generate n-Grams (Terms)" to_port="document"/>
          <connect from_op="Generate n-Grams (Terms)" from_port="document" to_port="document 1"/>
          <portSpacing port="source_document" spacing="0"/>
          <portSpacing port="sink_document 1" spacing="0"/>
          <portSpacing port="sink_document 2" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="mututal_information_matrix" compatibility="5.0.11" expanded="true" height="76" name="Mututal Information Matrix" width="90" x="277" y="219"/>
      <operator activated="true" class="text:wordlist_to_data" compatibility="5.0.7" expanded="true" height="76" name="WordList to Data" width="90" x="246" y="30"/>
      <connect from_op="Read RSS Feed" from_port="output" to_op="Process Documents from Data" to_port="example set"/>
      <connect from_op="Process Documents from Data" from_port="example set" to_op="Mututal Information Matrix" to_port="example set"/>
      <connect from_op="Process Documents from Data" from_port="word list" to_op="WordList to Data" to_port="word list"/>
      <connect from_op="Mututal Information Matrix" from_port="example set" to_port="result 3"/>
      <connect from_op="Mututal Information Matrix" from_port="matrix" to_port="result 4"/>
      <connect from_op="WordList to Data" from_port="word list" to_port="result 1"/>
      <connect from_op="WordList to Data" from_port="example set" to_port="result 2"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
      <portSpacing port="sink_result 3" spacing="0"/>
      <portSpacing port="sink_result 4" spacing="0"/>
      <portSpacing port="sink_result 5" spacing="0"/>
    </process>
  </operator>
</process>