Ok I think I got the answer that specific chemical is a high octane fuel used in motorcycles. If you looking Amanda holiday space in the bazaar on the tower she has a jug of it. As most of us know she is the shipwright for the tower and does work with sparrows as clearly seen and her space in the tower. And a sparrow is somewhat like a motorcycle.
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I noticed this number on the side of the post box in the helm as well. It may be a lubricant or something?