When it comes to unclogging a garbage disposal, there's a right way and a wrong way to do it. The wrong way is to reach into the disposal to do it with your hand. Even if it were possible to remove an obstruction with your fingers—which it rarely is—the consequences of a miscalculation are too severe to warrant the risk. The right way to clear a clog is to spin the rotor from underneath the sink. If you have an Insinkerator model, you can use the jam-buster wrench or a standard 1/4-inch hex wrench to do this. For other models, a regular wrench or a pair of pliers usually works. If you must reach in through the mouth to spin the rotor, do it with a broom handle or some other piece of wood, rather than your hand.
What's Causing the Clog?
Often we think the disposal is clogged when it is actually the drain. However, before you go to the trouble of disassembling the P-trap to clear the drain, you should follow the procedure for clearing the disposal itself because it's easier to do.
When it comes to the device's mechanisms, you might think your garbage disposal has a spinning blade inside, but few do. Most are made with one or two spinning impellers, much like the agitators inside a washing machine, and a canister with serrations on it like those on a cheese grater. The impellers are attached to a rotor. When the rotor spins, the impellers push food waste against the serrations. The shredded food then washes through a gap between the rotor and the canister. The gap isn't wide, so it's common for debris, especially stringy foods like celery, starchy ones like potatoes and small bones to get stuck. When the debris fills the entire gap, water can't pass through and it backs up into the sink.
Clearing the Garbage Disposal
The strategy for getting debris out of the gap is usually simple: Reverse the rotor, flush the disposal with water and then turn on the disposal and allow the debris to wash through.
Insinkerator Models: If you have an Insinkerator garbage disposal, you'll find a slot for a hex wrench underneath the garbage disposal in the middle of the rotor. Insert a 1/4-inch hex wrench or the jam-buster wrench that came with the garbage disposal. Use the wrench to spin the rotor back and forth a few times. Sometimes debris gets lodged so tightly that the rotor won't spin at all. When this happens, an internal breaker trips to prevent the motor from burning out. It may take some force to get the rotor going, but once it spins freely, press the red reset button. Next, turn on the water, start the disposal and the problem should be fixed.
Other Models: For models that are not Insinkerators, a nut may take the place of the hex slot. Other than using a regular wrench to reverse the rotor (instead of a hex wrench), the procedure for clearing a clog is the same. Note that the reset button may be located on the side of the canister rather than the bottom as it is on Insinkerator models. If you can't find anything to grip on the underside of the rotor, you may have to insert a wooden implement through the mouth of the disposal to reverse the rotor. Hook the implement on one of the impellers and use it as a lever to spin the rotor.
Clearing the Drain
If standing water remains in the sink after you clear the garbage disposal, the drain is clogged. To clear it, disassemble the P-trap at the point at which the curved section straightens out and heads into the wall. Loosen the nut with a pair of slip-lock pliers, remove it and swivel the curved section away. Loosen the other nut so you can remove the curved section and empty it. If you don't find the clog inside this section of pipe, it must be in the horizontal waste arm. Clear it with a sink auger.
Clogs can build up over time, especially if you regularly put potatoes, rice and other starchy or greasy foods in your garbage disposal. Once a month, you can use a simple method to help prevent starches and greases from building up. Performing this trick regularly means you may never have to use your jam-busting wrench.
Fill the garbage disposal with ice, then pour in half a cup of Kosher salt and allow the mixture to sit for about 10 minutes. The ice will harden any greases and starches that have collected in the gap. When you turn on the water and start the garbage disposal, the ice and salt will remove material from the sides of the serrated canister and carry all the gunk down the drain.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.