There is described a process for reducing the concentration of formate based heat stable salts formed in a physical solvent acid gas absorption process (12) wherein acid gas contaminants such as hydrogen sulfide and carbon dioxide are removed from gas mixtures (30) which include these contaminants. The process comprises the step of contacting the physical solvent containing formate based heat stable salts (46) with a metallic and/or organometallic catalyst (52), preferably the catalyst comprises palladium, zinc, platinum, nickel, or rhodium, and/or salts thereof and/or oxides thereof. The process is particularly suited for physical solvents such as refrigerated methanol, dialkyl ethers of polyethylene glycols, N-methyl-2-pyrrolidones, propylene carbonate, blends of N-acetylmorpholine and N-formylmorpholine, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, and the like and particularly gas mixtures containing ammonia as a contaminant.
