Methods for producing highly pure solutions containing hydrogen fluoride, one or more salts thereof or a mixture of two or more thereof, by adding hydrogen fluoride to at least one anhydrous solvent, wherein the hydrogen fluoride is added to the anhydrous solvent or solvents in the form of a gas or as a liquified gas or as a mixture of gas and liquefied gas. High purity hydrogen fluoride and ammonium fluoride solutions produced by the inventive method are also disclosed.