WHETSTONE | Free Game

You have to either wear the whetstone on your belt or hold it in your hand.

You have to wield the weapon you want to mend.

You then use the command whet to get your weapon back into good shape.

Note that using them requires a great deal of time and energy so you will lose movement points.

If no whetstone is available you can certainly mend your weapon at a local weaponsmith's shop.