That flux has been baked on so long it's turned to a varnish and the GP cleaner isn't even touching it. This is where Deflux-It G2 comes in. Slow-drying, solvent-based formula that stays on the surface long enough to break down waxes, oils, greases, and the toughest baked-on flux residues. Works on PCBs, micro BGA components, and sensitive assemblies without corroding them. Pleasant smell – not the chemical stink you get from most solvents. Safe on most plastics, elastomers, and rubbers. Leaded or lead-free, it doesn't care. Add to cart and finally get that stubborn flux off