How can I reclaim space used by the defaul email client The default email client on my phone is reported as have almost 2.5Gb of data.   It's used to sync with my work Exchange account.   I've reduced the number of days to sync and the number of folders to sync, with no reduction in the reported space used by the app.  I do notice that the trash folder claims 999+ messages, even though I delete the contents most days from my laptop client.   That folder doesn't offer sync settings, and I can't find a way to select all of the messages to delete them.

Short of clearing all data for the app and setting my account up again, is there any way to reclaim some of this space?
I ended up deleting the account and re-adding it.   Space used by Email went from 2.7Gb to 16Mb.

On my Moto X, running Android 4.4.4, Delete the account from System settings (i.e., not in the Email app) -- under Settings, in the "Accounts" section, find the account with the Email app's icon and name that matches the name in the app.  Tap the account name, then the menu icon, and select "Remove account".   Details may vary on other Android versions.

To add an account to the Email app, click the menu icon, then select Settings", "Add Account" will appear in the right side of the top menu bar.