Oil of Sharpness [Масло остроты]

Potion, very rare

This clear, gelatinous oil sparkles with tiny, ultrathin silver shards. The oil can coat one slashing or piercing weapon or up to 5 pieces of slashing or piercing ammunition. Applying the oil takes 1 minute. For 1 hour, the coated item is magical and has a +3 bonus to attack and damage rolls.

Source: D&D System Reference Document 5.1, © Wizards of the Coast LLC, licensed under CC BY 4.0.