If you can't see any damage or build up on the tap, it may simply require a little bit of additional force. Grab a wrench and gently but firmly turn the tap anti-clockwise until it begins to move. Be careful to not apply too much pressure, as you don't want to damage the tap accidentally.
Loosen it with a wrench.
Tighten a wrench around the base of the handle, and gently turn it. (To prevent scratches, wrap a cloth around the handle before applying the wrench).
Try heating the area around the faucet with a blow dryer or heat gun. The heat may help to expand the metal and loosen the faucet.
If you're looking to unscrew a faucet, grab a pipe wrench or a pair of adjustable pliers. Turn the faucet counterclockwise to loosen it. Sometimes, it helps to hold the faucet steady with one tool while turning with the other. If it's stubborn, you might need some WD-40 to loosen any rust or buildup.
Spray WD-40
If your notorious tap is still not working well, you will need to show the magic of WD-40. Take your can of WD-40 Multi Use Product, shake it well, and spray it on and within and crevices of your tap. Make sure you spray the liquid at all the right places, focusing on the areas from where the tap turns.
It is common for taps in our homes and gardens to get jammed due to a build-up of rust and dirt. But, if you need to loosen a stIff tap, instead of seeking help from a plumber, all you need is WD-40.
Apply Penetrating Oil
Particularly stubborn nuts could loosen with a few applications over 24 hours. If the nut has whitish lime deposits, remove what you can with a wire brush, then brush on white vinegar to dissolve what remains.
Clean or Replace the Faucet
Clean out the inside of the faucet valve with vinegar, and repeat the cleaning on the cartridge. Inspect for metal shavings, worn parts, grit, or mineral buildup. A scrub brush can help loosen deposits. Use the plumber's grease to lubricate any threads you can see.
Detaching and Cleaning the Cartridge
If it doesn't move, check your faucet's brand name because it will only move with a cartridge pulling tool from the same brand. If you successfully remove the cartridge, check if there's any corrosion—corrosion is the primary cause of tightening and stuck faucets.
Heat the Joint
In some situations, you may be able to soften that tight joint again by mimicking the chemical reaction with heat. Try using a hair dryer or blow torch to gently heat the area where the glue was applied. You can then twist and pull until the pipe is loosened.
You can try some WD40 or some hot water over the valve to try and loosen it. When you have undone the cartridge you will get a small amount of water seep out, have a cloth handy to mop up this water. Your cartridge may come out with an adaptor bush /conversion ring attached.
Just take a can of WD-40 (preferably one with a long flexible hose) and spray it inside of your faucet. The WD-40 will loosen up the hard water and make the diverter work as smoothly as day one. The same goes for a hard to turn shower knob, a sprits of WD-40 and it will work like brand new.
Commonly known as CRC, penetrating oil should be your first step in trying to loosen a nut, bolt, or screw. Spray the fastener and leave for 10 – 15 minutes to allow the oil time to penetrate the threads of the bolt or screw. Then use a wrench or screwdriver to undo the fastener.
Using the right sized spanner or an adjustable wrench, tighten the nut a little, then give it a wriggle before trying to loosen it again (remember righty tighty, lefty loosey!). Turn on the heat. Heat makes metal expand, so applying a little heat to the nut could make it expand enough to loosen.
Try using channel-locking pliers to get a grip on the aerator and turn it counter-clockwise to unscrew. If pliers don't work, apply heat to soften or expand the metal, or try spritzing the part with a penetrating oil like WD-40.
Grab your adjustable wrench and loosen things up. Just wrap a rag around the handle's base to avoid any nicks and scratches. Then, clamp the wrench on good and give it a twist counter-clockwise to loosen that stuck thing. Remember: Don't go Hulk smash on it – you could damage the tap.
Water-miscible cooling lubricants for taps
Because water conducts heat well, these lubricants are especially effective in dissipating heat generated during the machining process. Water-miscible coolants contain additives like emulsifiers, antioxidants, and corrosion inhibitors.
Sometimes, it can be overtightened, causing the tap handle to become stiff. Slowly turn the nut to loosen it, being cautious not to let water leak out. If you notice any limescale or scum on the nut, clean it off or consider replacing it.