You can do bulk mail deletion in gmail by following the given steps:
1. Login your Gmail account.
2. Next to the Search there is an arrow icon(show search options)Click it.
There would be various fields such as From,To Subject, Has the words, Doesn’t have etc.
3. In the “Has the words” field, type before:2013/03/01. Any date ; it would delete all messages received prior to that date.Create filter with this search.
4. Go to Next step.
5.Select the checkbox ‘Delete it’, then select ‘Also apply
filter to ### conversations below’.
6. Click ‘Create Filter’.
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