When you accept a job, you agree to the payment amount set by the property owner. However, there are ways you can boost your earnings on site. If you're on the lookout for issues that go above and beyond a standard clean (ex. a dishwasher that needs a deep cleaning, or a coffee pot that requires descaling), you can make more money and earn a reputation as a detail-oriented Service Provider.
Of course, you can't just decide to complete an extra task and charge the owner. If you spot an issue that's not outlined on your job's cleaning checklist, submit a Problem Report to the owner. Then, they can review your report, and sign off on the extra task (and your cost estimate for completing it.)
If they approve the extra task(s), you can add an additional cost/time/distance to the job before leaving.