Request your Twitter archive at https://twitter.com/settings/your_twitter_data. Extract the archive and checkout these files into the archive directory.

cd <extracted archive>
git clone https://github.com/jplock/tweet_purge.git
virtualenv venv
source venv/bin/activate
pip install -r requirements.txt

Create a new application on https://apps.twitter.com to get your Consumer Key, Consumer Secret, and generate an Access Token Key and Access Token Secret.

Create config.py

#!/usr/bin/env python

CONSUMER_KEY = ''
CONSUMER_SECRET = ''
ACCESS_TOKEN_KEY = ''
ACCESS_TOKEN_SECRET = ''

Adjust the number of days of tweets to delete in tweet_purge.py

delta = timedelta(days=30)

Then execute the script:

python tweet_purge.py