Whether deep-frying, browning ground beef, or cooking bacon, we often end up with leftover cooking oil. The tendency may be to pour it down the kitchen sink but that can clog and damage the plumbing, and if it's poured outside on the ground, it can cause problems for wildlife.
You can save your cooking oil to reuse later, but if it's gone bad or you don't want it, there some easy, safe ways to get rid of it. It's also a good idea to check with your local solid waste department to see if they have any disposal recommendations or regulations.
Reuse Cooking Oil
If you plan to deep-fry soon or fry foods on a regular basis, you can save the cooking oil to use again. First, strain the oil through a coffee filter or several layers of cheesecloth to remove any particles and crumbs. Then, pour it into an airtight container and store in a dark place until ready to use.
It is important to note that you should reuse oil only once or twice. Give it a sniff before using it; if it smells rancid, toss it out. Remember that each time you reuse oil, the oil deteriorates and the smoke point (the temperature at which it will burn) decreases.
Pour Into Disposable Container
If you want to get rid of the oil, let the oil cool completely, then pour it into a nonrecyclable container with a lid and throw it in the garbage. Common nonrecyclable containers that work well include cardboard milk cartons and similar wax- or plastic-lined paper containers. Styrofoam and other takeout containers are also good options.
Chill Until Solid
If you prefer to throw it out, you need to freeze or refrigerate the oil first to harden it. Pour the oil into an old can and put it in the freezer or fridge. Once the oil is solid enough to come out of the can in one piece, it is ready to be thrown into the trash.
If you have no more than a cup of oil or grease, pour it into a coffee mug and set it in the fridge. When it solidifies, scoop it out and drop it into the trash with a spoon. Then wipe out the mug with a paper towel or used napkin before washing it.
Pour Small Amounts Into Trash
If you have a small amount of oil, it can be safely disposed into a partially filled plastic trash bag. Just be sure to cool the cooking oil first and close the bag. Paper towels, food scraps, and other absorbent material help contain the oil so you don't have a pool of it that can potentially leak from the bottom of the bag.
Combine With Other Material
Before disposing, you can mix the oil with an absorbent material like cat litter, sand, and sawdust, which easily soaks up the liquid. Save old oil in a used container until it is time to empty the litter box; dump the oil into the litter before tossing out.
Purchase a Grease Disposal System
If you do a lot of frying, you may want to consider getting a grease disposal system kit that consists of a plastic receptacle with foil-lined bags that can hold up to 32 ounces of oil. Place a bag in the container and pour the cooled oil into the bag. When it is full, seal the bag and throw it in the garbage.
Recycle Cooking Oil
Some cities have collection programs for recycling used cooking oil into biodiesel. Check Earth911 to see if there's a recycler near you that will accept it. Biodiesel is a clean-burning fuel that is used in many types of motor vehicles (often city trucks and fleet vehicles) and can be used as heating oil.
Cooking Oil Disposal Don'ts
There are a few no-nos when it comes to getting rid of used cooking oil. Don't pour oil down the drain or in the toilet. It can clog not only your pipes but also the city sewer mains. You should also not add oil to a septic system. It can clog pipes and, even worse, your distribution lines and drainage field. Water contaminated with oil is difficult—sometimes impossible—to treat. This means it can eventually pollute local waterways.
Don't pour hot oil into the trash can, as it can attract insects and rodents as well as cause issues with garbage trucks and solid waste sites. You should also not dispose of cooking oil into compost bins or piles. Fats, in general, are bad for compost, and cooking oil is nothing but fat.