Reclaim storage space by removing old LFS objects

Hi,

Let say I store all my testing data in LFS. And let’s assume that one day, part of these test data files become obsolete and I don’t need them anymore in my tests… Doing git rm -rf <obsolete_test_data_files> will result as these files not being completely removed as they will still be stored in the gitlab storage space of my repo. I guess this is because the files are still referenced by some (old) commits in my git tree. Though I want them to be completely done and reclaim the storage space associated…

I found this tutorial on how to remove those reference and run the repository cleanup scripts.
This makes sense to me but my question is : how can I get a list of all the deleted lfs files that I can pass onto git filter repo ?

Thanks for you help,