My Mistakes

I have used  MYOB for a number of years but have made some errors these historic errors were not a concern to my previous accountant as just took a spreadsheet report for year for purcases and sales. I have changed to an accountant that actually works with my data in AccountingRight and has asked me to clear invoices in past years that have been paid but not recorded as paid Our sales are cash so no outstanding debts. Similarly with  purchases all have been paid but not recorded as paid. . 

Is there some way of getting the file straight  without resulting in further chaos and not having to work with each entry