Hi @janemnash,
You can check the Devtools mentioned by the user from within the application:
As you have confirmed all of the data is synced, you can clear the IndexDb by navigating to this link here:
C:\Users<user>\AppData\Local\Postman
C:\Users<user>\AppData\Roaming\Postman
Note: If any of your data isn’t synced to Web dashboard, deleting this folder will wipe the data permanently.