I am trying to reset my Cloud Shell disk. I am deleting projects and creating new, but getting same cloud shell with all pre-installed files. Is there anyway to reset completely.
Yes there is
Restore your Cloud Shell home directory to a clean state:
Check for personal files in the home directory:
ls -a $HOME
Remove all files from your home directory:
sudo rm -rf $HOME
In the Cloud Shell menu, click the gear icon, then click Restart Cloud Shell. Click Restart Cloud Shell in the confirmation dialog.
From the docs https://cloud.google.com/shell/docs/resetting-cloud-shell