This is something I should have done a long, long time ago. But was always far too lazy to do and ended up doing mass deletions of my inbox two to three times a day. I was subscribed to a lot of things. A LOT. Surveys, job alerts from other countries, diet tips, you name it, I had a subscription.
I started by going onto the websites and unsubscribing the long way and after about three felt like giving up again. Then I discovered Outlook’s nifty little “Delete all from sender” button which included the option of blocking all future messages.
Done and done.