1a. While holding the Option key: select the volume automation on any track. This will show the volume automation for every track. 1b. Alternately, if you use Key Command Focus (a...z), hit Option-"Minus Sign" (the one on the top of the letters section of the keyboard). This will also show the volume automation for every track, and it's much faster.2. With the Selector tool: click on any track, anywhere.3. Press Return. This will place the cursor at the beginning of your session.4. Hit Command-A (Select All). This will select from the beginning to the end of your session on all shown tracks.5. Hit Control-Delete. This will delete all automation of every type (volume, mute, pan, etc...) on all shown tracks.