Step 3 · Apply Penetrating Solution
With the set screw loosened, the handle is likely fused to the valve stem by mineral deposits (lime and calcium) or corrosion. To break this bond, generously apply a penetrating solution. Spray a quality penetrating oil, like PB B'laster or WD-40 Specialist Penetrant, into the set screw hole and around the base of the handle where it meets the faucet body. For stubborn mineral buildup, a descaler is more effective. Soak a rag in white vinegar or a commercial product like CLR, wrap it tightly around the handle's base, and secure it with a rubber band. Let the chosen solution sit for at least 30-60 minutes; several hours may be needed for severe cases.