Deletion Flag on production orders with variances

Hello Friends,

We use product cost collectors in discrete production environment. We have a lot of production orders from past with WIP. We want a way to put a deletion flag on these order and take the differance as a loss. I know this is not right, but cleaning up all the old orders is too much of a job. So please let me know if there is a way to put a deletion flag on the production orders with variances or WIP. Thanks in Advance