The easiest way to empty your trash in email is in landscape mode, on the left hand column at the top you will see Edit press this and the column will shift to the right, go down the column pressing on the emails to delete, once you have them all selected, press delete which is at the bottom. It's simple and this is the fastest way to empty the trash. You can also go to Settings - Mail, Contacts, calendars -select your mail account, it will load with a small window. Select Advanced at the bottom and then you will see the option to Remove Deleted Messages, set this how you like. Hope this helps you.
The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.
This is the most time consuming activity that the iPad has next to reading an iBook publication. Why can't they add a feature as delete all emails before a certain date. I now have 6000 emails that I have to individually remove.