If you do your own engine oil changes, you’ll end up with several quarts of dirty oil.
How should you dispose of it?
First, you need to get it ready for disposal.
* The best way to transport the oil from your home, via car, is to carefully transfer it from your oil drain catch pan to empty/used gallon jugs – such as leftover household detergent containers, etc. A funnel is helpful for this job, as is a drain pan that has a built-in pour spout. You can even buy a drain pan with a sealable lid and spout designed specifically to make it easier to take the old oil to a recycling station; however these can still be unwieldy for the average person to deal with — especially if they’re really full.
* Be sure the oil is cool before you attempt to transfer it to the empty jugs. Those jugs may melt or burst open if you pour still-hot used oil into them. Screw the cap onto the jug and make absolutely sure it is on tight. For extra security, you can slip the jug into a plastic trash bag and twist that closed with a tie-twist. Get an old cardboard box, put a layer of newspaper down on the bottom. Put the jug in there.
* If you have a truck, the best place to put the oil jug for transport is obviously the bed since if it does leak, it won’t be a disaster. Be sure it’s secure nonetheless (use tie downs or something heavy to keep the jug where you put it; and of course drive gently. If you have to use a car, avoid transporting the oil in the trunk. It is most likely to tip over or roll around as you drive, which could leave you with a foul and pretty much impossible to ever clean-up mess. The ideal place is actually the passenger side floorpan. It should be relatively flat and more important, you’ll be right there to keep an eye on it as you drive.
So, where to actually take the oil?
* One option — probably the simplest for most people — is to to bring the old oil to a gas station that accepts old oil for recycling. These days, some stations charge a small fee for this, so it may be necessary to “shop around” a little. Depending on where you live, there may be pubic recycling bins available for the old oil filter, too.
* Another option (especially if you live in a rural area) is to ask around until you find someone who uses a commercial-type oil-fired stove to heat their place. Car repair shops and other commercial places are likely prospects. These places will be happy to take your old oil for free, because for them, it’s free heat. If you do find such a “source,” consider getting a larger capacity container such as a 5-8 gallon gasoline jug. You can then use this as your old oil depot (it’ll take several oil changes to fill that thing up) and then, once a year (or whenever) you can cart the jug to your friend with the heat stove.
* Gear oil (such as transmission/axle fluid) is generally ok to dispose of in the same way and mixed in with used motor oil.
* Old engine coolant/automatic transmission fluid should not be mixed with used motor oil if you’re giving it to someone for use in their oil-burning stove. If you’re just hauling this stuff to a gas station pick-up point, it may be ok to mix it all together. But ask first.
Also: Try to limit the amount of oil that gets on your skin and the amount of time it stays in contact with your skin. Old oil (and other such fluids) contains lots of stuff that is not good for your health. Wear gloves – and wash your hands as soon as possible.
And remember that certain fluids — antifreeze in particular — may taste good to animals/pets but can kill them if they lap some of it up. Don’t leave spills unattended — and clean them up as soon as possible. Cat litter, believe it or not, is great for this job.