That's not very environmentally friendy, now is it?
Waste cooking oil
Proper disposal of used cooking oil is an important waste-management concern. Oil is lighter than water and tends to spread into thin and broad membranes which hinder the oxygenation of water. Because of this, a single liter of oil can contaminate as much as 1 million liters of water.[7] Also, oil can congeal on pipes provoking blockages.
Because of this, cooking oil should never be dumped on the kitchen sink or in the toilet bowl. The proper way to dispose of oil is to put it in a sealed non-recyclable container and discard it with regular garbage.[8]
Cooking oil can be recycled. It can be used to produce soap and biodiesel.[9]
http://en.wikipedia.org/wiki/Cooking_oil
How to Dispose of Used Cooking Grease
by eHow Food & Drink Editor
Introduction
Disposing of used cooking grease is an environmentally important task. There are several ways to safely dispose of it, but it should never be poured down the drain.
Steps
1 Allow the oil to cool completely before disposing of it.
2 Decide whether the oil needs to be discarded. Oil used for deep-frying can usually be reused several times. Strain it into a clean sealable container.
3 To throw it away, carefully pour it into a strong sealable container, such as an old plastic jar with a lid. Many households save jars for this purpose. Plastic jars are better than breakable glass ones.
4 If the amount of oil is small, place the filled, sealed jar in the trash.
5 Take large amounts of cooking oil to the local landfill.
6 Alternatively, recycle large amounts of used cooking oil with the help of a cooperative local restaurant. Most restaurants have used grease bins, whose contents are recycled into consumer products. Ask if you can add your used oil to their grease bin.
7 Used cooking oil can also be composted with other organic matter. If you have a compost heap or a healthy backyard earthworm population, feed them kitchen scraps.
Tips & Warnings
Save sealable plastic jars or old coffee cans for disposing of old grease.
Wait until the oil has cooled completely before handling it.
Never pour oil down the drain. Even small amounts will eventually clog the plumbing.
http://www.ehow.com/how_15918_dispose-used-cooking.html