Cleanline 7000 is a very low residue flux core wire solder designed for no-clean hand soldering applications. The flux core provides sufficient activity to solder successfully to bare copper and other demanding applications. The unique blend of resin and proprietary non-halide activators provide rapid wetting, while leaving minimal levels of post-soldering residue. This residue is optically clear, soft and easy-to-probe, tack-free and non-corrosive. In some circumstances and over time the residue can have a white milky appearance.