For some older Macs this won't necessarily be the latest OS, such as MacOS Monterey, but instead MacOS Catalina, for example. Your computer should then install the latest version of OS that it can install. If you want a clean 10.6 installation, you'll need a DVD.
There are several tutorials on how to make a bootable USB drive in which case you could boot in to the installer, wipe the disk, and install a clean Yosemite.
To reinstall your Mac's OS without an installation disc you need to firstly make sure that you keep your Mac turned on during the whole procedure, and that your Mac is connected to the internet. All has been well until the upgrading from OS 10.6.8 to 10.11 to 10.12. Small but perfectly formed, the AnyDesk remote desktop for Mac is fast to download and easy to install.
Step 8: Close Disk Utility and and from the OS X Utilities menu select ‘Reinstall OS X’ as shown in the screenshot below. Click the Erase button to format the drive. In this article we will show you how to reinstall Mac OS without disc. Step 7: On the right, select the Erase tab, followed by selecting 'Mac OS Extended (Journaled) as Format for the drive.
If you want a clean 10.6 installation, youll need a DVD. MacOS includes a recovery partition that allows you to easily erase all data on your Mac and reinstall your OS without an installation disc. If the MacBook supports Yosemite (the latest OS version), then you could download the installer from the App Store.