DEAR TIM: My wife has been fighting with a stinky garbage disposal. It's relatively new (I replaced it for other reasons last year). She's tried many different approaches to cleaning, and yet to her the smell returns. Before I pop the drain pipe and see if there's something accumulating down there, do you have any tips for cleaning a garbage disposal? Leo N., Seattle, WA

DEAR LEO: This is pretty simple to solve but because you now have an odor problem, it is going to take a little work. Let me explain what has probably happened over time. The inside surfaces of the garbage disposal get a slime on them because I suspect the disposal is not being used properly.

Many people simply throw garbage down into a garbage disposal, turn it on while some water is running through it and quickly turn the disposal off as well as the water. The spinning motion of the disposal blades throws a slurry of garbage up on the sides of the disposal chamber and the small amount of water coming from the faucet doesn't always completely wash this organic slurry off the sides of the disposal.

If this slurry of organic debris is not completely washed off the inside of the disposal, it begins to rot and this decomposition produces a foul gas. If you do this enough times - meaning not rinse off the organic slurry, it can harden over time and then becomes a problem to clean. You have to re-hydrate the hardened slurry.

The proper way to run a garbage disposal, in my opinion, is to put the garbage in it and grind it up with a strong stream of water running from the faucet. Once you have finished grinding all of the garbage, immediately place the stopper in the large hole at the bottom of the sink and fill the sink with water. As the water is filling the sink, add a generous squirt of liquid dish soap. Fill the sink at least 2/3 the way with water.

Once the sink is filled with this soapy water, immediately remove the stopper from the sink and quickly turn the disposer back on. If you could see inside your disposal, you would see a wild vortex of action.

Because the sink was filled with water, the inside of the disposal fills with water the instant you remove the stopper. The spinning blades of the disposal agitate this soapy water inside the disposal and this completely washes the sides and all parts of the disposal.

There is another bonus benefit to this rinsing operation. The actual drain pipe leaving the disposal and all downstream pipes get thoroughly flushed. Often kitchen drain pipes and the plumbing branch line that connects the sink to the main plumbing drain line leaving your home get clogged with the slurry produced by a garbage disposal. People simply do not let water run long enough after the garbage is ground up.

If you don't let perhaps a gallon of water run in the sink after the garbage disposal makes that high-pitched noise telling you the garbage is gone, the slurry of organic debris is not carried completely out of your house. It can take 30 or 40 seconds of running water to fill a gallon container. My guess is you rarely run the water that long.

To remove any hardened food slurry deposits from the inside of your garbage disposal, you are now going to have to do a small amount of plumbing work. Go to a real plumbing supply house and purchase a rubber test cap that has a stainless steel tightening band on it. This clamp is just like a muffler band clamp. Plumbers use these temporary test caps to close off the ends of pipes for either water or air pressure testing required by a plumbing inspector.You should be able to find one made for 1 and 1/4 inch diameter PVC schedule 40 pipe that will fit perfectly on the 1 and 1/2 inch diameter tubular pipe leaving the disposal.

Disconnect the pipe that leaves the disposal from the drain system piping under your sink or from the p-trap under the sink. Attach the rubber test cap to the end of the tubular pipe leaving the garbage disposal and tighten the clamp. Place an empty five-gallon bucket under the end of this pipe in case the clamp leaks or slips.

With the rubber test cap in place, start to fill the disposal with very warm water. If you purchased the right clamp and you have the clamp tightened just right, the disposal will act as if it is clogged and the water will begin to back up into the sink. Stop running the water as soon as the level reaches the top of the chrome strainer basket in the bottom of the sink that connects to the disposal.

Now add one-half cup of powdered oxygen bleach to the garbage disposal filled with water. Oxygen bleach is non-toxic and will not harm you, the garbage disposal, the plumbing system or septic tank should your home be connected to one.

Once the powder is added to water it begins to create millions of tiny oxygen ions that start to soften and attack the rotten, hardened garbage on the sides of the disposal and any slurry on the side walls of the drain pipe leaving the disposal. The oxygen bleach solution, if left in the disposal for up to an hour, does a fantastic job of sanitizing the unit.

After letting the oxygen bleach solution work inside the disposal for an hour, loosen the clamp on the rubber test cap and let the water rush into the bucket. Reconnect the disposer to the plumbing drain system and perform the same operation as described above as if you had just ground up some garbage. In other words, insert the stopper into the sink, fill the sink with warm, soapy water, remove the stopper and turn on the disposer.

Once you have done this, the disposer should be as clean as the day it was installed. It should also smell as good as the day it was installed!

Some people have tried placing ice cubes in a smelly disposal to clean it. The problem is you can't be sure the chips of ice will clean off all of the hardened slurry.

If the disposal is smelly, you are going to have to clean it the right way just once. After that, if you rinse it thoroughly after each use, it will never give you a problem. An odor problem that is!

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Author's Note: I received the following tip from Julian L. not too long ago. I thought it was a good addition to this column and am happy to share it with you. Thanks, Julian. TC

In 2007, my InSink Erator garbage disposal developed a severe blockage, which I  attempted to fix as follows.

STEP ONE:
Thinking that I had loosened the motor enough from the disposal's bottom with a 1/4" Husky Allen Wrench, which is definitely more effective than a regular one (with a small handle), I did the following.

1. Depressed disposal's bottom pushbutton.
2. Inserted and locked disposal's magnetic cover.
3. Flipped disposal's wall switch to on.

Subsequently, I heard some spinning but the motor soon stopped. Although I hadn't succeeded, I felt good knowing that the motor was still alive.

STEP TWO:
I then realized that the blockage was still there.  With power off, I continued turning the motor in both directions repeatedly with the wrench until I felt that the motor was turning relatively freely.  To me, the wrench is a great tester because it tells me whether a blockage is still present or not, major or minor.

STEP THREE:
Suddenly, I thought of using WATER PRESSURE to help overcome the residual blockage as follows.

1. Ensured disposal's wall switch was off.
2. Inserted and locked disposal's magnetic cover.
3. Stored plenty of cold water in sink.
4. Depressed disposal's bottom pushbutton.
5. Flipped disposal's wall switch to on.

The disposal now started to spin and continued spinning! It still worked after I had turned the power off and back on.

CONCLUSION:
Gist of my idea: I use water pressure to re-enforce and sustain the motor's initial spinning. In a very difficult case, it is this re-enforcement that ensures the unclogging. No matter how bad the clogging is, one can always create enough water pressure to overcome the clogging (by storing enough water in the sink prior to running the motor). The principle of my idea applies to other disposal brands also.

Message from Tim: Years ago while researching a column about cleaning decks, I discovered the wonders of Oxygen Bleach. It is perhaps the 'greenest' cleaner I know of as it uses oxygen ions to break apart stains, dirt and odor molecules. There are no harsh chemicals, and it works on just about anything that is water washable. I decided to create my own special blend using ingredients made in the USA. In fact, the raw materials in the active ingredient are food-grade quality registered with the FDA. I call my product Stain Solver. I urge you to use it to help with cleaning your garbage disposal. You will be amazed at the results!

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Comments: Welcome! I, Tim Carter, don't answer questions here. If you post a question here in the Comments Area, perhaps another visitor will help you. You need to go to the Ask Tim page if you want a question answered. Once there, look closely at how many weeks behind we are. Please be patient as you use this free service. If you have an emergency and need to talk to me, there is an option there for you. Steve 24 Jan 2008, 06:26 I've tried a lot of these remedies to no avail. The last thing I tried was to use a brush and thoroughly clean the underside of the rubber splash guard. Inseting the brush all the way into the disposal, and pulling up on the splash guard, inverted the rubber upwards for easy cleaning. There was quite a bit of sludge and was apparently the cause of the smell. The stopper had a build-up of sludge around the rim as well. nick 06 Apr 2008, 19:00 the rubber splash guard on the ISE models is replaceable, and not expensive. the tricky part is removing the bottom of the disposal unit to remove and refit the new one. while it is apart, you can check for sludge on the inside of the unit more easily. nick 06 Apr 2008, 19:05 by the way, I did try Tim's trick and it worked well for me. When I had taken off the transvers pipe from the disposal side to the 1 1/2" vertical piece, the entire transvers pipe was coated with about 1/2" of the black sludge as well, so for 8 bucks I replaced this pipe and the rest of them down to the p-trap. with the cost of the rubber splash guard and the pipes, it was about 3 hours (2 trips to store) and 20 bucks. I also replaced the rubber gasket on the side of the disposal that prevents leaks as the water leaves the disposal the nice thing about ISE models is that most of this stuff is available and not expensive. It is also interchangeable between models, in many cases. J.E. Adamson 13 Feb 2009, 10:26 My dishwasher empties into the garbage disposer grinding cavity and then dumps into the waste line. When my dishwasher goes into a rinse cycle I will turn on the the garbage disposer which "power flushes" the disposer, and cleans the waste line in one operation. I have been doing this about once a week for the last 8 years and never had an odor problem from the disposer. Robert 25 Feb 2009, 14:45 I just wanted to share a tip. The pipes on our kitchen sink are an odd 1 1/4 inch. I looked everywhere for a plumber's test cap of that size and could not find anything. One place assured me that the disposal would have a 1 1/2 inch drain even if there was a taper, but even the disposal was 1 1/4. So, in case anyone else has this problem and lives in a small town with limited resources, I folded several layers of aluminum foil and molded it around the drain pipe, covered that with a freezer bag, then tightened up a hose clamp around it. I put a bucket underneath just in case, but there was only a small drip. I wish I had tried this before making four unsuccessful trips (six if you count two returns). BTW, thanks for this great article. My disposal is cleaning now and I can't wait for that smell to finally be gone! Mari Barker 20 Apr 2009, 10:03 Hi There, I just found this site when I googled sump pumps, but when I saw a garbage disposal odor question, I really got excited. We have a garbage disposal on the left side of our sink, but there is a foul odor coming from the other side's drain. Is this from the disposal? Because the disposal side doesn't smell at all. K. Engels 26 May 2009, 15:32 I have a problem with a rotten vegetable smell coming from under the sink. The disposal smells fine from the top side and the dishwasher smells fine. We have taken apart all the pipes and there is no smell in them. There is no leak under the cabinet....Could the disposal motor be smelling? Curtis Thompson 11 Jun 2009, 13:50 I to have the same smell as K. Engels has. I have even put in a new garbage disposer and still have the smell coming from under the sink. If anyone has a suggestion on this problem please let me know. Thanks Curtis Mark 16 Jun 2009, 21:45 Hi there, After reading some of the comments about the garbage disposal odour problem, is it possible that tis could cause odour coming from basement drain pipe, even if the disposal is upstairs? K. Engels 17 Jun 2009, 10:09 Smell under the sink: I am pretty sure that this is not a disposal problem because the disposal smells fine - top and bottom. Mark suggests that this may be a drain pipe problem. Although we are on a slab and there is no basement, my next plan of action is going to be to take off all the pipes and tubes under the sink and see if there may be a crack in one of the pipes or tubes that is leaching drain pipe smells. Thanks much.      View all comments *Name: Email: Notify me about new comments on this page Hide my email *Text: Security Image: Security Image Text:   Remember, Tim Carter doesn't answer questions here in the comments. You need to go to the Ask Tim page.