Yeah, phosgene gas is produced heating chlorinated brake cleaner. Phosgene gas is a military weapon.
When TIG welding certain metals cleanliness is critical. along with wire brushing a good solvent is needed that dries quickly with no residue. Some use acetone with a paper towel, or cloth. The towel is sure to contain something that would contaminate, If the metal has been ground to clean it,it'll tear tiny bits from the towel, causing another problem. Non chlorinated brake cleaner is a perfect solution. In an aerosol can, no lint is left behind.