To win all indestructable weapons hold ctrl-alt-shift
and type win.
Here's how to dupe an item without any hacking:
1. Use Town portal.
2. Set any item in front of the portal.
3. Click with the mouse on the item and step
through the portal.
4. When you reach the town the item will be in
5. Go back through the portal and the item will be
where you left it.