Most of us are aware that we can clean all but the most recent System Restore Point, by using the in-built Windows Disk Cleanup utility.
We open the Disk Cleanup utility > Clean up system files > More Options tab > Free more disk space by removing all but the most recent restore point > Click Clean up > Apply/OK.
Delete all old System Restore Points
But if you wish, you can also clean up ALL the old system restore points, along with system settings and previous versions of files, natively in Windows 10/8/7.
To do so, To do so open Control Panel > System and Security > System and click on System protection.
Next, under Protection Settings, click to select the System Disk and then click Configure.
Here click on ‘Delete all restore points (this includes system settings and previous versions of files).