Inventory List Problems

[ADEAN10]

We are a nursery and we want to input a new inventory list, the old one was set up incorrectly and now the average cost of the plants are wrong and affecting our P&L report. I wanted to see if there was a way to change just the average cost of the item or if I can delete the item list and start over (which would be better). But when I try to delete an item it tells me we can't because it is in use on a transaction.


What can I do to get rid of the item that has the average costs that are wrong? Do i make them inactive and re-put it in.