A full week of paid work is the plate. What remains after that plate is cleaned looks like a thin oil film: Saturday morning, a Sunday hour, the gap after dinner on one weekday. Those pieces are real. They are also short. If they smear across the week they dull sleep, the commute, and Monday.
A burnisher is the rod that turns a scraper edge keen. It does not remake the tool. It takes one pass. Leftover hours work the same way. Write a maximum. Put that block on the plate. If an offer needs every weeknight, it is not leftover work; it is a second job wearing leftover clothes.
What sits in one pass
Start with one visible block. Saturday morning is the default used on this desk because it does not steal weeknights by default. A person can add a Sunday hour or one weekday evening. Adding every evening is not leftover time. That is a second shift.
Write the start and the stop before the week begins. A block that is only "when I have energy" slides off the plate. The day job will take it.
What dulls the main week
Unpaid setup that has no end date, learning that is sold as a condition of the first invoice, and work that needs a weekday night every week do not belong on this plate. Those strokes dull the rest of the week.
Burnisher does not publish earnings promises. The question is whether leftover hours can sit still long enough to be counted, priced after costs, and marked in a weekly record. If they cannot sit still, they are not leftover.
Read next: polishing until they take a keen edge and a weekly wipe of the record.