I’m submitting to flash fiction contests/open calls. My false starts and cut scenes give me material to submit to them. It’s best not to just copy and paste. They still need editing to become a self-contained story. Yet it’s still simpler than having to write from scratch. If you have a complete scene, it’ll have its own cutoff point but you may need to add more detail to set the scene.
I just started doing this, so I must report back on the results at a later date. So far I like the thought of salvaging my past efforts even if they didn’t pan out into a full story or novel.