Like I literally can't find any way

why would you use that thing literally nobody uses it.

anyways,if my memory doesnt fails me,i think after the other clan accepts the war,before you accept prizes,there you offer items that are in your deactivated.

of course,that,it has been a very long while since i last started a war,so im not completely sure

Whenever I click offer items, it says no changes made

Even though i've things in inactive

Good question, same here