Sell Lemons Sewer Key Guide

Complete lever puzzle solution, Cosmic Cash Vine location, and how to get the UFO Key that permanently doubles your rebirth investor bonus.

Worth doing immediately — the UFO Key is the best free upgrade in the game. It doubles your investor bonus per rebirth (+1% → +2%) and costs nothing except a short puzzle. The Cosmic Cash Vine also gives a large cash payout every 4 hours.

Lever Puzzle Solution

Pull the colored levers inside the sewer in this exact order. One wrong pull resets the sequence.

1
2
3
4
5
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7

Full Sequence (copy this)

Blue → Red → Green → Red → Blue → Purple → Red

7 steps total. Do not skip any step or pull a wrong lever — the puzzle resets to step 1 if you make a mistake.

What's Inside the Sewer

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Cosmic Cash Vine

A special cash-generating plant that resets every 4 hours. The payout scales with your current income level — harvest it every time it resets for a significant cash boost.

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UFO Key Puzzle

After the lever puzzle, navigate deeper into the sewer maze to find the second puzzle. Solving it grants the UFO Key, which permanently doubles your rebirth investor bonus from +1% to +2%.

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Good Samaritan Badge

Connected to the UFO Key quest. Completing the sewer sequence unlocks this badge and the associated rewards.

UFO Key — Why It Matters

Without UFO Key

  • → Each rebirth grants +1% permanent investor bonus
  • → F2P maximum: 1% per rebirth
  • → After 100 rebirths: +100% permanent bonus

With UFO Key ✓

  • → Each rebirth grants +2% permanent investor bonus
  • → F2P maximum: 2% per rebirth
  • → After 100 rebirths: +200% permanent bonus
  • → 2× the long-term growth for free
The Double Investors gamepass can push beyond 2% per rebirth (up to 32% max), but the UFO Key gives you the same F2P cap with zero Robux cost. Always get the UFO Key before buying any gamepasses.

Sewer Key FAQ

Where is the Sewer entrance in Sell Lemons?

The Sewer entrance is located in the basement of your tycoon. Look for a trapdoor or tunnel entrance beneath your main building floor. The entrance becomes accessible once your tycoon is established.

What is the lever puzzle solution?

Pull the levers in this exact order: Blue → Red → Green → Red → Blue → Purple → Red. The sequence must be completed without error. If you make a mistake, the puzzle resets and you start over.

What is the Cosmic Cash Vine?

The Cosmic Cash Vine is a special plant deep inside the sewer that rewards a large cash payout when harvested. It resets every 4 hours, making it a reliable periodic income boost. The cash reward scales with your current income level.

What is the UFO Key and how do I get it?

The UFO Key is obtained by solving a second puzzle inside the sewer, accessible after completing the lever puzzle and entering deeper into the maze. Getting the UFO Key permanently doubles your investor bonus per rebirth from +1% to +2% — a massive F2P upgrade.

Does the lever puzzle reset?

Yes. If you pull levers in the wrong order, the puzzle resets and you must start the sequence from the beginning. Go slowly and follow the exact sequence: Blue → Red → Green → Red → Blue → Purple → Red.