Also if that isn't possible to clear the old postings, can I use period end maintenance.

GL Periodic Processing - Clear History will allow clearing of journal entry batches and posting journals. 

To clear transactions is part of "Create new year". Set the number of years to keep in Setup-Options. Then when you run Create new year the old transactions will be removed automatically. 

We have a Purge History utility that will simplify purging of data across all modules.

www.musick-int.com/.../PurgeHistory.pdf 

Hi Oladejo Joy, if this suggested answer helped, please do mark it as verified  (by clicking the "more" button on the response) for the benefit of others in this forum . Thank you!