The Fortnite x Pirates of the Caribbean collaboration brings new skins, items, and a series of Cursed Sails missions. Some of these missions are basic, while others require you to do pirate-themed things, like finding Jack's favorite Jar of Dirt.
How to EASILY collect a pot of soil and deliver it to Jack Sparrow – Fortnite Pirates Quest
This is a two part mission, part of the Pirate Code One missions. Here you can read how to find a Jar of Dirt in Fortnite and deliver it to Jack Sparrow.
The first step is to find the Jar of Dirt. You can find it next to the abandoned train south of Nitrodrome. Land where the tracks are covered in sand and go to the back of the train. On the south side of the train you will see a marker with the Jar of Dirt to interact with.
Be aware that this location will likely be highly contested. Since others can't "steal" the quest item, you can land nearby to collect some loot (like a new Flint-Knock pistol) and wait for players to kill each other.