You can just create a new branch before you start the rebase, which achieves exactly the effect you ask for. Rebase is how you "create a new branch with only the clean commits".
But, most of us don't bother copying before rebasing. The reflog makes that pointless from a safety perspective and, without the safety need, there's not much reason to copy before rebasing.
But, most of us don't bother copying before rebasing. The reflog makes that pointless from a safety perspective and, without the safety need, there's not much reason to copy before rebasing.