Since the inception of Professional Chem-Dip Carburetor and Parts Cleaner (current part #0905) in the 1950s, the primary ingredients have been cresylic acid, methylene chloride, and sodium dichromate. Cosolvents and additives have changed a little as government regulations and chemical shortages have both affected what additional components we’ve been able to use. However, it is fair to say that the current formula is still substantially similar, being comprised of aromatic and chlorinated hydrocarbons.