Whetstone (5e Equipment)
From D&D Wiki
Made from a type of stone used to sharpen slashing and piercing weapons like swords and daggers, this specific piece of stone is made to be easy to handle with a single hand while attempting to use it. The whetstone is also commonly used to help remove rust from some types of armors and weapons.
When you spend 1 minute sharpening a single non-magical weapon or up to 5 pieces of non-magical ammunition, a whetstone will grant that item a non-magical +1 bonus to attack damage for the next 8 hours and 1 hour less per every battle. No weapon or piece of ammunition can benefit from more than 1 whetstone bonus at a time. This action can be done during a short or long rest as well. This whetstone has no effect on magical items of any kind.
Cost: 1 cp
Weight: 1 lb.