* Strain it through a few layers of cheesecloth to catch any food particles. Be careful with hot oil, though, because you can easily get burned.
* Shake off excess batter from food before frying it.
* Use a good thermometer to fry foods at 375°F.I use a inf-red temp gun.
* Turn off the heat after you are done cooking. Exposing oil to prolonged heat accelerates rancidity.
* Don't mix different types of oil.
* Store oil in a cool, dark place.
* Avoid iron or copper pots or pans for frying oil that is to be reused. These metals also accelerate rancidity.

HTH