Hey Maris, Related post https://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=155137

Run at own risk! 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using EPiServer.PlugIn;
using EPiServer.ServiceLocation;
using EPiServer.Web;
using System.IO;
using EPiServer.Framework.Blobs;

namespace Gosso.Episerver.ScheduledJobs
{
    [ScheduledPlugIn(DisplayName = "CleanUpFilesJob", Description = "This job iterates all blobs on disc and removes the ones that does not exists in CMS", SortIndex = 10105)]
    public class CleanUpFilesJob : EPiServer.Scheduler.ScheduledJobBase
    {
        public override string Execute()
        {            
            var blobpath = new FileBlobProvider().Path;
            string[] dirs = Directory.GetDirectories(blobpath, "*", SearchOption.AllDirectories);
            var tobeRemoved = GetBlobsToRemove(dirs);
            Remove(tobeRemoved);
            return "Removed blobs: " + tobeRemoved.Count;
        }

        private void Remove(IReadOnlyList<string> tobeRemoved)
        {
            foreach (var blobPath in tobeRemoved)
            {
                Directory.Delete(blobPath,true);
            }
        }

        private IReadOnlyList<string> GetBlobsToRemove(IReadOnlyList<string> allBlobPaths)
        {
            var blobsToRemove = new List<string>();
            var mapper = ServiceLocator.Current.GetInstance<IPermanentLinkMapper>();

            foreach (var blobPath in allBlobPaths)
            {
                var guid = Guid.Parse(blobPath.Split('\\').Last());
                var map = mapper.Find(guid);
                if (null == map)
                {
                    blobsToRemove.Add(blobPath);
                }
            }

            return blobsToRemove;
        }
    }
}

Thanks, Luc! This looks great!

Would be better if Episerver would have this scheduled job :)