Message archive hit SQL express max size

After less than 3 months our DB is pegging the SQL Express 4GB max size threshold. I’ve turned off Message Archiving for now, but is there a way I can go and drop old data from the DB? Anything more than 3 weeks old?

I can backup the DB, then drop old data and turn it back on, and just do this on a monthly basis while I contemplate moving to MySQL or Postgres.