Straighten out a wire clothes hanger as much as possible. Bend one end slightly to create a small hook capable of fitting into your sink drain. Slide the wire hanger down, hook-side first, into the drain. Try to keep the wire pressed to the side of the drain rather than pushing it down the center of the pipe. Doing so will minimize the risk of pushing the blockage further down. Once you feel resistance, twist and maneuver the hanger in an attempt to hook the blockage. Pull the wire back up to remove as much of the blockage as possible. Run hot tap water from your sink and into the drain for a couple of minutes. Make the water as hot and rapid as possible, but if the sink starts to back up, turn the water off.
If you are working with a sink that has two sink drains, hold a wet cloth tightly over one drain to seal it off. Place a plunger over the other drain, holding it fairly upright. Fill the other side of the sink with 3 to 4 inches (7. 5 to 10 cm) of water. Doing so helps the plunger seal around the drain. Roll the head of the plunger into the water, forcing water into the drain. Pump the plunger up and down for a solid 20 seconds using a vigorous, rapid motion, but do not break the seal between the plunger and the drain. Pop the plunger off the drain on your last vertical upstroke. You may need to plunge the sink for several minutes in order to loosen the blockage.
Place a large bucket below the trap. This will catch any water or debris that falls from the pipe once you remove the trap. Use slip joint pliers to loosen the slip nuts on the trap and unscrew the nuts by hand. Slide the nuts away from the connections and carefully slip off the trap. Use a small wire brush to scrap out any debris from the trap, emptying it into the bucket below. Also clean the trap out by scrubbing with the same wire brush. Carefully rinse the trap with hot water. You may want to use another sink, since you just removed a portion of the drain pipe for the sink you are currently working on. Reattach the trap to the rest of the piping. If any slip nut washers show notable signs of wear, replace them.
Remove the P-trap and any pipes that connect to the drain stub-out at the wall. Pull out 6 to 10 inches (15 to 25 cm) of snake cable. Thread the tip of the snake into the drain stub-out. Tighten the setscrew. Turn the crank clockwise to feed it into the pipe. Any initial resistance you feel is likely caused by turns and corners the snake must make. Once you hit a blockage, continue cranking until you feel the tip of the snake cable break through to the other side. The tension in the cable will be reduced dramatically after it breaks through. Turn the crank counter-clockwise to pull the cable out. Clean the cable as you remove it. Repeat as needed until you no longer feel any blockage and restore your piping to its usual state.
If possible, flush the sink out with at least 4 cups (1 L) of water. Use more if your kettle will hold it. If you do not have a kettle, you can boil the water in a saucepan or electric hot pot. You could also use the microwave to boil water, but microwave the water only in 20 to 40 second intervals and keep a wooden chopstick in the water as it microwaves. Otherwise, the water could super-heat and present a danger. Pour the boiling water directly down the drain, rather than pouring it into the sink first and letting it gradually flow to the drain. Note that this works best on minor clogs and may not prove as effective against heavy clogs. The water must also be boiling as you pour it since the vibration of the water is part of the reason why the remedy is effective at all.
Pour 1/2 cup (125 ml) baking soda down the sink drain. Follow the baking soda with 1/2 cup (125 ml) white distilled vinegar. Quickly cover the drain opening with a drain stopper. Doing so forces the fizzy reaction down through the pipes, where the blockage is, rather than up and out. As soon as the fizzing stops, pour another 1/2 cup (125 ml) white distilled vinegar down the drain. Cover again and let sit for 15 to 30 minutes. Boil 1 gallon (4 L) of water in a kettle or saucepan. Pour the boiling water into the sink to flush out any remaining vinegar and baking soda.
Combine 1/2 cup (125 ml) table salt and 1/2 cup (125 ml) baking soda. Carefully pour or spoon the combination down the sink drain. Get as much into the drain as possible, and avoid getting too much excess on the basin of the sink. The reaction will only be effective against the blockage if it comes into direct contact with it. Let the baking soda and salt sit for 10 to 20 minutes. Boil 1 to 4 quarts (1 to 4 L) of water in a kettle or saucepan. Carefully pour the boiling water into the drain. Plug up the sink drain as quickly as possible after adding the water to force the reaction down into the pipes rather than up and out. The chemical reaction produced should be enough to clear most moderately clogged sinks.
Caustic soda can be purchased at most hardware stores. Dilute 3 cups (750 ml) of caustic soda with 3/4 gallon (3 L) of cold water in a large mop bucket. Mix the chemical and the water together with a wooden spoon. Do not use any container or utensil you plan to use for food later on. Do not stir the water and caustic soda together with your hands. The water and caustic soda should begin to “fizz” and heat up as you mix the two together. Carefully pour the solution directly into the clogged sink drain. Let sit for 20 to 30 minutes without touching it. Boil 1 gallon (4 L) of water on the stove and use it to flush the drain. Repeat the procedure if necessary.
Pour 1 cup (250 ml) of undiluted bleach directly down the sink drain. Let sit for 5 to 10 minutes. Turn your sink on and let water rush into the drain. Make sure that the water is as hot as possible and as strong or rapid as possible. Let it run up to 5 minutes. If your sink begins to back up and fill with water, turn the water off and let it drain before attempting to unclog the sink again. Do not use bleach if you use a septic tank. Bleach kills bacteria living in the tank, but the bacteria it kills eats solid waste, thereby preventing the lines from clogging.
Read the label carefully to determine which cleaner is right for your particular type of blockage. For instance, some cleaners might work better in bathroom sinks, while others might work better for kitchen sinks. Follow the instructions on the label carefully when you use it. Caustic drain cleaners rely on chemical reactions caused by hydroxide ions. Acid drain cleaners use a chemical reaction between hydrogen ions and the material clogging the sink. Acid cleaners tend to be harsher than caustic drain cleaners. Enzymatic cleaners are the least potent and rely on bacterial enzymes to eat away organic blockages.