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

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