As of a few weeks ago, when you remove a car from your app, it and all its data are also removed from the Web Dashboard. If you're using Gen 1 or 2 with the Classic App, you can remove the car yourself in the app*. If you're using Lite or Pro, Tech Support will need to remove the car for you so please send an email to firstname.lastname@example.org.
Please note that once a car has been removed, you will no longer be able to access the data from that car unless you still own the car and run through setup again.
*If you've removed the car from the Classic app but it's not disappearing, please follow these steps: