Floor B2: Boilerworks

Elevator Hall: Head left for Gold Bars behind the elevator. Defeat Gold Rats to the east for Gold. Use Dark Light near the east shelves to reveal a ladder leading to Gold Bars and a chest with Money. Open the toolbox on the left for Coins, slam boxes for Gold, and send Gooigi through the green pipe for more Coins. Suck up Coins from the light above the elevator. Use your plunger on the bottom-left lid to reveal a hole; defeat the three Bats that emerge for Bills.

Boss Encounter: Head east to meet Clem, the floor's boss. After a cutscene, Clem leaves through the eastern door. Slam the desk for Gold and suck up Coins from the thick pipe above.

Key Puzzle: Turn the valve with your Poltergust if bothered by running water. Suck up the cloth section of the wall next to the pipe on the left to reveal a hidden pipe. Enter the pipe to retrieve the Key. Before returning to Luigi, head left through a hidden entrance to find the Yellow Gem. Give Luigi the Key and enter the eastern door.

Waterworks: Defeat the two Goobs. A third Goob and Mini Goobs will appear; defeat them.

Water Puzzle: Send Gooigi through the pipe to the right. Luigi must control valves to allow Gooigi to progress. Turn all valves to the right initially. Then, turn all three valves to the left. Take Coins from the bucket and flash the strobe switch to open the door. Blow into the fan on the right as Gooigi to release Money for Luigi to collect. Enter the eastern door.

Reservoir (Skip for now): Skip this large room and focus on a smaller room in the southwestern corner. Stun the Rat on the way.

Storage Room: Send Gooigi through the pipe to an empty area. Take control of Luigi. Slam the yellow cleaning bucket to reveal a second pipe. Enter this pipe. Suck up junk, open the chest for Gold, suck up pizza boxes and the banjo for Coins, suck up Coins under the bed, take Bills from the shelf, tear off bed sheets for Coins, suck the dragon on chains for Coins, and take down the box on the green pipe for Gold. Slam the box on the right to reveal a pipe. Enter this pipe to reach the underground room. Water blocks the Red Gem. Control Luigi and blow on the valve to remove the water. Take the Red Gem. Leave the room.

Reservoir (Revisited): Use your Suction Shot on the glass bubble-like window to the north for Bills. Use Suction Shots on two more windows to the right for Coins. Slam the box to the east for four Gold Bars. Journey counter-clockwise to find two more boxes with Coins and a toolbox with Gold. Blow on the fan to the south to rotate the central platform.