You will need a plumber's wrench, a screwdriver, a bottle brush with a long handle, a pair of rubber gloves and a bucket. The first thing to do is to unplug the waste grinder. If it is not plugged under the sink go to your circuit breaker panel and throw the switch off. Make positively sure that it is off, food grinders are very dangerous. Now take a look under the sink, on the bottom portion of the drain there is a curve that has a cover screwed on it. Loosen it a little with the wrench and place the bucket underneath. Take the cover off and let all the water in it fall into the bucket. Give it a few minutes until water starts dripping and remove the bucket.
Once this is done you must take it apart. You will see that it is made up of different pieces held together by large nuts. Sometimes the drains are metal and sometimes they are plastic so be careful not to damage them during removal. If you have two sinks instead of one there will be pipes coming out the bottom of each sink joined by a tee that is screwed to another pipe that goes into the wall. The first step is to loosen all the nuts holding the pieces in place. Sometimes this can be done by hand, if not use the wrench.
Start from the middle; remove first the pipe that goes from the curve and connects with the pipe going into the wall. Do not try to move or pull the pipe going into the wall, it is sealed in there with cement, if you move it or try to pull it out you may cause a leak which the plumber will have to fix. So just let it be. Remove the curve and tee followed by the pipes which are screwed to the bottom of the sink. When removing the pipes be extremely careful so as not to lose the plastic rings on the inside. These are gaskets which prevent leaks at the pipe joints.
If you have a waste grinder in place, remove it by loosening the screws which hold the metal strap attaching it to the sink bottom with the screwdriver. As you remove each piece of pipe keep them together in the same position they were under the sink to avoid confusing them or putting them in the wrong place while re-assembling the drain. It is clean-up time, using the circular bottle brush with soapy water clean the inside of each pipe. When finished inspect them carefully to make sure there is no food residue stuck inside. Now take the waste grinder, turning it upside down and making sure you do not get any water into the electric circuits, clean the inside. You may use your water hose to add cleaning pressure in order to remove the gunk inside. Inspect it and you are now ready for re-assembly.
You must now put it back together in the same manner you removed it. Start with the waste grinder screwing it tightly in place. Make sure you push it up to the same position it was before, not more not less. Do not over-tighten it; you may ruin the screws holding it in place. Just make sure it does not wobble or move. Now comes the tricky part, remember that the pipes coming from the sink and waste grinder fit into the tee, put them in place without tightening the nuts, tighten them enough to stay in place but lose enough for you to be able to move them some . Do not forget the plastic sealant rings. Now fit the tee in place and tighten all the nuts coming from the sink and waste grinder and into the tee. Again do not over-tighten them, just enough so they do not move. Do the same with the curve leading to the pipe in the wall.
Now to check your work, open the water faucet so you can check for leaks. If there are any, just tighten the nuts a bit until the leak stops. Reconnect your grinder and the electricity supply to it, put some water inside and turn it on, again, check for leaks and adjust any necessary nuts and screws. If there are no leaks you are done, if these persist, take apart the leaking pipes and make sure the plastic ring is in place, re-tighten and all should be fine. Congratulations in half an hour you have saved yourself some money and have prevented your sink from suddenly clogging.
Source by Cesar A Batres Mejia