Sell Lemons on Roblox looks like a straightforward idle game on the surface, but underneath the main street sits a maze-filled sewer system with a hidden puzzle that most players never figure out on their own. Crack it, and you unlock the Sewer Gate, gain permanent access to the Cosmic Cash Vine, and earn the Cosmic Farmer Badge. The catch? You need to pull four colored levers in a specific sequence, and the maze itself will happily send you in circles if you don't know the layout.
What do you need to do before entering the sewer?
Drop into the sewer through any manhole cover on the main road. Just stand over one and you'll fall straight through. Once you're down there, use the center of the sewer where the two scoreboards stand as your navigation anchor for every step of this puzzle. The two boards are the Most Cash leaderboard and the Most Fruits Picked leaderboard. Knowing which one you're facing at each stage is what keeps you oriented.
Drop through any manhole
What is the correct lever sequence for the Sewer Key?
The full sequence has seven steps. Get them out of order and the pathway to the Sewer Key won't open. Here's the breakdown:
Pulling Blue, Red, and Green first unlocks the route to the Purple Lever. You then need to reset both the Red and Blue levers to the unpulled position before the Purple Lever path becomes accessible. After pulling Purple, pulling Red one final time opens the door to the Sewer Key's hidden location.
How to find the Blue Lever
Face the Most Cash leaderboard so the green wall text is on your left. Head left down that path and take the first right. From there, follow the right-side path and ignore the red floor lines. At the next junction, take the second right. Continue forward past the first right turning, then look for a green line on the floor to your left. Take the hallway to the right of that green line.
At the next fork, take the left turn (the one with the red line), then follow the path marked with the purple line. It's a long linear corridor from here, but stay on it and the Blue Lever is waiting at the end. Pull it once.
Blue Lever at maze end
How to find the Red Lever
Face the Most Fruits Picked leaderboard so the green wall text is on your right. Go straight ahead instead. You'll pass a locked gate on your right as you move down the hallway. Enter the maze opening on the left and follow the only available path straight to the Red Lever. This is the most straightforward lever in the entire puzzle.
How to find the Green Lever
Face the Most Cash leaderboard again (green text on your left), but this time go right instead of left. Walk to the end of that hallway and take the left path into the maze. Ignore the first right turn and keep to the left. Take the first right after that and stay right. At the end of that hallway, turn left onto the path with the blue and red floor lines.
Follow the linear route until you hit two left turns. Take the first left and continue. The path gets winding with several dead ends branching off, but stay on the main route and watch for a small turning on the right. The Green Lever is down that turning.
How to find the Purple Lever
With Red and Blue both unpulled, head down the hallway leading toward where you found the Blue Lever (face the Most Cash leaderboard so green text is on your right this time) and stick to the left side. You'll spot an open hallway. Enter it and take the right path first.
Continue through to the other end and take the second right, then another right after that. When you reach a path with a red floor line, take the right branch and continue forward. At the end, turn left and follow that route to the Purple Lever. Pull it down.
Purple Lever unlocks final path
How to collect the Sewer Key
After pulling the Purple Lever, respawn or teleport to the surface, then drop back into the sewer. Head to the Red Lever and pull it down one more time. A door opens on your right. Go through it and follow the path until you see a purple floor line on the left side. Take that route.
At the next crossroads, take the right path. Continue forward until you spot a green floor line leading right, then take it. At the next turn, look for a blue floor line and take that turn. Immediately after, take the left path and the Sewer Key is at the end.
How do you get the Cosmic Farmer Badge?
Carry the Sewer Key back to the Sewer Gate in the main sewer area and unlock it. Inside, you'll find the Cosmic Cash Vine. Harvest it once and the Cosmic Farmer Badge is yours immediately.
The Sewer Gate stays permanently unlocked after that first harvest. The Cosmic Cash Vine respawns every 4 hours and pays out a random amount of Cash each time, making it a solid passive income source worth checking back on regularly.
For more hidden content and farming systems in Sell Lemons and other Roblox titles, the full collection of Roblox guides has you covered. If you're playing Sailor Piece alongside Sell Lemons, the guide on how to get Boss Keys in Sailor Piece covers a similar key-farming loop that's worth knowing, and the Sailor Piece Sea 2 unlock guide walks through the next major progression step once you're ready to push forward.