
I place them on top of the hot tub water to soak up the oils (thanks Reddit!). They seem to work better than the floating ones I've used.

Liqui Moly 2001 Valve Clean
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Synthetic engine oil LIQUI MOLY Molygen New Generation 5W-40, 4 l, 4 kg, 1 piece
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ACDelco GM Original Equipment 10-9243 Dexron VI Full Synthetic Auto Transmission Fluid - 1 qt: Top-Quality Performance for Your Vehicle
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Convenient New Pig 57703 Universal Mat Plus Dispenser Combo Pack - The Perfect Absorbent Solution
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