brown gas
n.— «Besides saving gas money, using what is called “brown gas” makes the car drive smoother, cleans the engine and is better for the environment, Bogue said.…Under his hood, Bogue filled six quart-sized jars with water and baking soda, covered them with vacumn-sealed plastic lids, installed a charcoal filter and connected it all with tubes to the car’s air intake system.…Besides saving gas money, using what is called “brown gas” makes the car drive smoother, cleans the engine and is better for the environment, Bogue said.» —“Baking soda boosts mileage” by Karen McIntyre-dn Daily News (Red Bluff, California) May 7, 2008. (source: Double-Tongued Dictionary)
Further reading
She sells seashells by the seashore. Who is the she in this tongue twister? Some claim it’s the young Mary Anning, who went on to become a famous 19th-century British paleontologist. Dubious perhaps, but the story of her rise from seaside...
Ribbon fall. Gallery forest. You won’t find terms like these in most dictionaries, but they and hundreds like them are discussed by famous writers in the book Home Ground: A Guide to the American Landscape. The book is an intriguing collection...
Still a scam. It takes more energy to make the gas than it gives off when burning.