possible?

I assume you mean to remove a pool with mostly deleted posts.
While pools like this may not be useful to users, they are to administration as it keeps them sorted if we need to undelete them.

Yes, but only admins are able to do this.

Also take into consideration that in some cases the pools are containing paid material which is under two years old, meaning that after two years it's much easier for everyone that they are simply restored instead of creating new pool, uploading new stuff and then tagging them again.

We can just switch them to inactive instead so they don't appear in the Add to pool list.