Continuity mistake: After Jack has escaped from the island where he was going to be burned, the makeup on his face (the eyes) changes between scenes. The makeup has faded quite considerably when he first boards the Black Pearl then in a later scene the makeup is neater and clearer. (00:42:30)
Continuity mistake: While Elizabeth listens as Captain Bellamy tells his crew that the stowaway is likely naked, she drops the paint brush into the pail. When it cuts to the close-up, the paint brush handle rests much higher in the pail. (00:46:05)
Continuity mistake: In the row boat, on their way to Tia Dalma's, when Gibbs discusses the Kraken, the large tear at his shoulder is visible, as are other imperfections on the tattered vest. Later, the tear disappears and other things change as well. (00:47:10)
Continuity mistake: In Tia Dalma's shack, when Tia Dalma approaches Will saying he has a touch of destiny about him and that he wants to know her, Will was standing in the door and took a few steps forwards, his back to the door. But when Jack runs to separate them, if you look through the gap between Tia Dalma and Will, they are now standing sideways to the door. (00:49:00)
Continuity mistake: At Tia Dalma's, when Jack says, "Look, an undead monkey," and shoots the monkey, the flame of the candle above the monkey is extinguished from the gunfire. However, in the next shot that candle is burning brightly. (00:49:30)
Continuity mistake: At Tia Dalma's, the key cloth is placed on the table, and in following shots the things such as the cloth, bones and jewelry scattered on the table change position. (00:51:50)
Continuity mistake: When Jack and the rest arrive at Tia Dalma's, the two slim candles on her table keep changing height, as do other candles. (00:52:20)
Continuity mistake: Tia Dalma gives Jack a jar of dirt (brown, clotty-ish), but later in the movie, it is sand. (00:53:10 - 01:57:30)
Continuity mistake: After Tia Dalma hands Jack the jar of dirt, the jar is positioned differently within Jack's grasp between shots - note the lid. (00:53:30)
Continuity mistake: During the scene in which the Black Pearl endures a strong storm and heavy rainfall, Captain Jack Sparrow's bandanna is soaking wet. In subsequent scenes, only moments from the storm, his bandanna is completely dry. (01:00:50)
Continuity mistake: Aboard the "spirit bride" ship, when Captain Bellamy complains about port tariffs, he places two small papers on the desk (atop the map) in the close-up, yet there is only one in the next shot, as he adds more papers. (01:03:10)
Continuity mistake: When Elizabeth is playing puppeteer with her wedding dress in order to get to Tortuga, she sweeps the dress past the captain's windows first, in order to get their attention. No way could she have done this from the mast on which she was standing. One, the distance between her position and the area through which the dress passed by were too far. Two, even if it were close enough, the wind was blowing at least partially against their sails, and the dress would have been blown closer to the windows. Three, even if she just stood on the deck above the captain's windows, she would not have had enough time to move from that position to the mast considering that the men in the captain's quarters rushed out to see the "spirit." (01:03:20)
Continuity mistake: The actual position of the burning word "Tortuga" differs between the first shot as it begins to burn on deck and from the close-up of the flames. (01:04:15)
Continuity mistake: When Elizabeth sits on deck and points out the burning word Tortuga, the wound lines beside her change position between the shot facing her and the next shot, behind her. (01:04:30)
Continuity mistake: Whilst Elizabeth puppeteers her wedding dress, in the close-up Captain Bellamy stands up and says, "Over there," as he points with his left arm extended. However, in the next overhead shot, it is his right arm that is extended as he points. (01:06:50)
Continuity mistake: When Captain Bellamy and his sailors stand on deck, looking at the flaming Tortuga, their positions differ between the shot facing them and the next shot, from behind. (01:07:10)
Continuity mistake: When Gibbs interviews potential crewmen in the Tortuga bar, things on the table change position between shots, and the height of the three candles differ as well. (01:07:30)
Continuity mistake: When Will Turner is to be given the lashes by his father, his shirt is torn up the back, with only the collar remaining intact on the back of his neck. In subsequent shots, the shirt is completely off his neck, back and shoulders, even as seen from the front. After his lashes are completed, his shirt is shrugged back on, with the neck in the back intact again. (01:11:30)
Continuity mistake: On the Dutchman, when Jones holds out the whip for Bill Turner to use on Will, the whip's direction flips between shots, it faces the opposite way when Bill grabs it. (01:14:20)
Continuity mistake: When Elizabeth speaks with Jack at the dock, about finding Will, her white pointed collar repeatedly jumps over and under the brown leather strap, at her right shoulder. (01:14:20)
Answer: The jar was to put Davy Jones heart in. He can't touch dirt ever again since he failed to keep up his duties which means he wouldn't be able to get his heart back.