Is there a way to delete old/irrelevant uploads?

I have even tried to destroy posts via ruby console. Even after that uploads are still kept on the server.

I used this exact rake task. When it finished all of my old uploads were still kept on the server. After that I rebaked all of the posts with uploads to update picture links.

This setting is enabled on my site for as long as I can remember.

Not exactly. I am more concerned with uploads users don’t even have access to. For example, user creates a post with picture in it and site administrator deletes this post. Picture in this post will be kept on the server. And I don`t see any timeout on that. I can go and take a look on posts which were deleted more than a year ago and all uploads are still there, they even have migrated to S3.