It's something of a misconception that a garbage disposal has blades. If you look into the mouth of your disposal, you'll see two oblong impellers attached to the rotor plate, which is the part that spins, but they aren't sharp. Their purpose is to fling food toward the shredder ring on the side of the canister where the actual food mashing takes place.
The impellers are designed to spin freely — the better to fling food — but they sometimes freeze up or come loose. When they freeze, you can use a simple trick to free them, but a garbage disposal with loose mounting screws on the impeller will rattle loudly and will need servicing. It's not a good idea to try to do this yourself, but you can remove the garbage disposal yourself so you can bring it in for servicing.
How to Loosen a Garbage Disposal Blade
Even though the impellers aren't actually blades, it's fair to identify them as such for the purpose of repair. When they freeze up, the garbage disposal won't work properly, food will be poorly ground and the disposal will probably clog up frequently. You can test for frozen impeller blades by turning off the disposal and testing the movement with a wooden implement, never your fingers.
If the impellers are stuck, Insinkerator, a major manufacturer, recommends putting steak or pork chop bones in the disposal and grinding them completely. The company assures consumers that this is safe, even though it makes a horrendous noise. If you're squeamish about grinding bones, you can probably get the same results by grinding ice cubes. If this doesn't work the first time, try again.
After grinding the hard objects, look into the mouth of the disposal and you may find a piece of metal, such as a coin, that's making the rattling sound. Remove it with tongs or pliers, again, never with your fingers.
The Garbage Disposal Impeller Plate Is Loose
When the mounting bolts on the impeller plate are loose, you'll hear a rattling sound, but when you look into the disposal, you won't see any foreign objects. Test the impellers by pushing against them with a wooden implement. They should spin freely, but they shouldn't have any back and forth movement.
If the impellers are loose, or they're stuck and you can't get them to spin freely, the repair calls for disassembly of the garbage disposal. People handy with home appliance repair may want to do this themselves, but most people will prefer to have the disposal professionally serviced. Whether or not you have the skill to do it yourself, keep in mind that professional service is required if you want to keep the warranty.
How to Remove the Garbage Disposal
If you have a garbage disposal with loose mounting screws or frozen impellers, turn it off and disconnect it from power, either by unplugging it or turning off the breaker. If the unit is hardwired, remove the electrical terminal plate and unhook the wires. You don't have to do this if the unit has a plug.
The next step is to disconnect the P-trap, so make sure to put a bucket under the sink because it will be full of water. If you have a dishwasher, loosen the clamp holding the drain hose and remove the hose.
Remove the disposal by grasping it with two hands and turning it counterclockwise by 1/4 turn to free it from the mounting bracket. It's heavy, so hold on tight to prevent it from falling. You can then remove it from the cabinet and call a service pro or attempt the repair yourself with the help of the manual.