No, this is not about saving the car engine oil, it's about the precious cooking oil that we use to fry foods with. Peanut oil is outrageous in price... something like $13.00 a gallon and Canola is around $10.00. A barrel (42 gallons) of oil is now around $45.00... heck, that's about a dollar a gallon! Gasoline is even cheaper, but, don't try to fry your chicken in gasoline... it might not be nice; colorful maybe, but not nice.

So let's save a few dollars by reusing the frying oil. First of all reusing cooking oil is somewhat dangerous in that food particles and after a period of time could be subject to bacteria growth...oil is not indefinitely good!!! Another fact I read about is that every time you use the same oil the smoke point decreases. That means the oil will smoke and taste bad at lower temperatures. Read more here...

Now let's figure you're going to save some oil to be reused. Let's now look at filtering... that's a key to the reduction of bacteria growth. How can we filter it quickly and in a simple manner? Two funnels and coffee filters or paper towels.

Buy yourself two of the same sized funnels. Now cut one funnel in half and leave the other just as is is. You can cut the funnel with a hacksaw. Clean up the cut edge with sandpaper. The first picture below is the top or "cut" funnel.

Now, take a coffee filter and put it in the bottom of the uncut filter and put the other cut funnel on top of it.  Below is setting the filter in place in the uncut filter, then put the cut funnel on top of it

Here is "the rig-up" with everything in place. I put a few clothes pins on it to hold the funnels together since the top one will want to float a little and I don't have four hands.

It's going to take some time as you progress because the filter will clog up. Change the  filter when you think you should.

Many people don't filter their oil, I know that. I'm just not a big fan of taking chances. One other point is flavor of the final product and here's what I do. Save seafood frying oil to be reused for seafood frying. The same holds true for chicken. Oil holds flavor (except in certain cases for Peanut oil). 

If I fry seafood that will include oysters, the oil if being dumped. The oyster flavor stays.

I also use the same oil only twice; that's me. That cuts my oil cost in half and maintains the good outcome of the final product.