@kellyr2
That's not a stupid question and I'm not sure my way is the best way. To zero out invoices, I change the amounts on all products/services to $0. If you delete the invoice, it would put any inventory items back in stock which you don't want. Then, I make a note (in the description field of each product/service or one of the message boxes) with the original invoice amounts. You can take a screenshot and save it as an attachment if you prefer. That way, if the customer ever comes back and can pay the invoice, you have a copy of the amounts.
