Abstract: This invention relates to a process for producing acidic aqueous solutions of melamine-aldehyde type polymers, and particularly melamine-formaldehyde polymer, which have significantly reduced levels of free aldehyde. The process involves the addition of hydrogen peroxide and/or iron in the form of ferric ion to the acidification stage of the production of melamine-formaldehyde polymers. When the process is conducted at elevated temperatures, in the range of 150-180.degree. F., iron is not required to cause destruction of the free formaldehyde. At lower temperatures the presence of iron may be required to achieve satisfactory rates of reaction. The process reduces levels of free formaldehyde to less than 0.1% by weight, such that the polymer solution may be used in a variety of applications with reduced environmental risk.