I have discovered some old vendor invoices and credit memos from prior years that I know have been paid and or used on the vendor side of the equation. The accountant prior to me did not keep track of what was paid and used very well at all. The result is I have many open invoices and credit memos from prior years in my QuickBooks that don't belong there.

I was thinking about creating one large credit memo to removed all the invoices at the same time. However because they are from prior years I am nervous if this would impact our prior years tax returns?  I know I don't want to delete or void them since they are from a prior year, so I am trying to figure out the best, cleanest way to handle them. 

As far as these old credit memos from prior years are concerned I really don't know what to do with them since I don't want to delete or void them either and mess up our prior years tax returns.  I guess I could create a fake vendor invoice in the amount of all these credit memos and apply them all to it?

Thanks for all your input!