Good evening :o
In my project I have imported a lot of assets, and I want now to remove everything that I haven’t used. Is there any easy way to do this? except deleting the assets one by one it is confusing and it takes time.
thank you,
backup the project before doing this. With the editor running, go in the content folder of the project in the windows file explorer, and delete everything. All assets that are being used will refuse to delete. All assets that are getting deleted were useless. Voila!
Hope that does what you want 
Hello,
i have the same problem here. Over 4 GB of tiles in my project…
Kind regards,
halobungie
huh, thats actually a good idea. brute force deleting works for me, but yeah, that method look cleaner.
Selet all game scenes and migrate to new proyect
This is the correct answer most of the time. Scenes tie your game together, migrating those will chain everything else along.
This doesn’t work 
- At least as a method for cleaning out a project to reduce its size.
You are not offered the choice of ‘migrate to a new project’ - just to a folder.
So I made a new project then tried migrating to that but just had a new project - NOT a copy of my old project cleaned.
Anyone know of the current best way to do this?
Best
Mark - total noob but loving it!
this is how all migration works, you have to direct it to the content folder of the new project you created
You can also select the persistent level from level streaming and migrate the current visible environment.
- create a clean blank project
- migrate the persistent level to the clean project
Only assets “used” with in the visible environment will be migrated and in the process fix all of the re-director paths in the process.
as well
You do not need to select sub-levels to migrate as long as the persistent is selected.
Some useful info
If and when you move a folder Unreal 4 will maintain a phantom folder containing a redirector as to where the asset has been moved to to ensure that asset paths are not broken. If you remove these “phantom/ghost assets” improperly the redirector will no longer exist and the next time you load the project you will get a lot of missing elements and materials.
When you migrate the persistent level the phantom assets till show up in the migration list but will be fixed as to their true locations. So no not a bug but a feature 
Thanks guys - I’m starting to get a handle on it.