Each week Fortnite will give out a new mission that contains different challenges. Finishing these challenges can get you free loot and lots of experience. The challenges can range from killing other players, looting chests, and visiting specific locations on the map.
For the named locations like Retail Row, Sweaty Sands, and all the rest, this is quite easy. You head to the town and do what the challenge wants you to do. Some are not that easy, as the game is filled with Landmarks that will not be marked on your map. There are 60 of them in total, and sometimes you will need to head to a specific Landmark for a challenge.
For the Forged in Slurp mission, you will need to visit a place called Compact Cars. It is a Landmark, so it is not shown on the in-game map, but we know exactly where you need to go.
The location of Compact Cars is shown on the map above, right between Dirty Docks and Frenzy Farm. It is precisely what you think, a small scrapyard where cars are crushed or compacted. You might find some chest here, upstairs in the building itself, and also in the doghouse. Some guns can also be found amongst the crushed cars, so be sure to gather it all up before you leave.
Remember for the Forged in Sludge mission that you will need to dance at Compact Cars, so be sure to bust out some moves before you head to a new part of the map.