If you want to re-use tokens, give the tokens multiple uses and append ?newtest=Y to the survey URL. I think that should start a new response.
Make sure "Enable token-based response persistence" is set to NO - manual.limesurvey.org/Survey_settings#Tokens
Make sure "Enable token-based response persistence" is set to NO - manual.limesurvey.org/Survey_settings#Tokens