diff --git a/lib/tasks/avatars.rake b/lib/tasks/avatars.rake
index bb37dc0e80e..cbbdd27596e 100644
--- a/lib/tasks/avatars.rake
+++ b/lib/tasks/avatars.rake
@@ -6,7 +6,20 @@ task "avatars:refresh" => :environment do
   User.find_each do |user|
     user.refresh_avatar
     user.user_avatar.update_gravatar!
-    putc "." if (i+=1)%10 == 0
+    putc "." if (i += 1) % 10 == 0
+  end
+  puts
+end
+
+desc "Clean up all avatar thumbnails (use this when the thumbnail algorithm changes)"
+task "avatars:clean" => :environment do
+  i = 0
+  puts "Cleaning up avatar thumbnails"
+  puts
+  custom_upload_ids = UserAvatar.where.not(custom_upload_id: nil).pluck(:custom_upload_id)
+  OptimizedImage.where("upload_id IN (?)", custom_upload_ids).find_each do |optimized_image|
+    optimized_image.destroy!
+    putc "." if (i += 1) % 10 == 0
   end
   puts
 end