The first method of getting rid of your dog waste bag is to put it in a trash can. The second option is to flush it down the toilet. However, any bag can only be flushed down the toilet if it is water-soluble. DO NOT dump the dog waste bag down the toilet unless you are certain it is made of water-soluble plastic. Composting is the third option for getting rid of dog feces. If this is your preferred form of disposal, degradable bags will suffice; but, for the finest compost, use biodegradable dog waste bags.