Whether you have a standard coffee brewing machine, an espresso machine or a French press, coffee bean oil will gradually build up on your filter if you use your coffee maker regularly. Cleaning it once a month or more will ensure you don't have layers of oil affecting the taste of each brew. Simply rinsing with water won't help much when it comes to oil. Harsh cleansers may be more effective at removing oil as well as calcium and lime deposits, but you can also use gentler, natural cleansers such as vinegar that won't harm you if there are traces left behind after cleaning.
Mix one part white vinegar and two parts water. Use enough to fill your coffee pot, French press, or espresso machine.
Pour the vinegar and water into the press or the machine and let it sit for a few hours.
Turn on the machine and let it run as if you were brewing a pot or making a shot of espresso. If you have a French press, push the plunger up and down to get the vinegar flowing through the filter. Repeat this process as many times as you wish. If you clean it regularly, once may be enough.
Rinse the pot or press and filter thoroughly. If you have a machine, run it again using clean water without the vinegar. You may need to do this a few times to get rid of the vinegar taste completely.