Are you one of those Facebook users with over 1,000 friends? Do you know them all? Personally, do you know them?

Even if you don't know all of your Facebook friends, you likely have them on your friends list for a reason. But, have you interacted with them lately? Do they post valuable things on your timeline, or are they just sitting on your friends list?

Duster, a free web app for Facebook, can help you cleanup your friends list. The app is simple; You give it permission to access your friends list and it goes to work from there.

Duster will analyze your friends list and see who you haven't interacted with recently, or at all. It will formulate a list of recommendations of who to remove, or "dust", from your friends list. But, don't worry, it won't automatically delete any of your friends, you have to do the deleting yourself.

In addition to suggesting who to delete, Duster also offers a "hide" feature. Using hide won't delete the person from your friends list but it will stop them from flooding your timeline with annoying cat videos or tiring jokes everyday.

There's a hidden bonus to Duster, too. When you get your list of recommendations, you'll be able to tell who you haven't interacted with lately on your list. Maybe it was an accident and you lost touch with an old friend. Duster will tell you that. So, instead of deleting them, maybe you want to send them a message!

Two computer science students at Boston University developed the app that basically shows you who you are friends with in name only.

Be warned though, if you go through a big spring cleaning of your friends list and delete a bunch of friends, it can lead to anger. No one wants to be defriended! So, get going and defriend wisely with this useful app.

Duster, the free app, is available here.