After trying several SQL statement queries I stumbled upon a built-in editor for CLOBs in SQL Developer:

  1. SELECT the affected table record(s)
  2. Double click on the column in the row you want to change
  3. Should see a pencil icon on the right hand side of the field
  4. Click on the pencil icon
  5. Should bring up clob in text editor
  6. Make changes
  7. Hit OK
  8. Hit Commit icon