Can I factory reset a jailbroken iPhone 5s

Do this instead:

1. Download or update iTunes to the latest version.
2. On the device, head to Settings > iCloud and disable Find my iPhone/iPad if it's on.
3. Connect your iOS device to your Mac or PC using the USB cable, and select it when it appears in iTunes.
4. On the Summary tab, hit Restore.

You can simply use a third party FonePaw iPhone Data Recovery software to factory reset your iPhone.

Just plug it in to iTunes and restore. Do not backup.

I would assume you have two options. You can:

1) Use the factory reset option under General>Reset

2) As mentioned in other comments, connect your Iphone to itunes and use the restore function to factory reset your device

Have a wonderful evening/morning/afternoon!