Whether you're cooking up crispy bacon or deep-frying breaded treats, leftover cooking grease can pose a garbage conundrum. Although most grease is reusable, eventually you have to toss it out. Pouring grease down the sink can harden and cause a clog, so proper disposal depends on what's offered by your local trash collectors.
The way you choose to package used grease depends on your disposal method. A metal container, such as an empty coffee can, or a waxed cardboard box, such as an empty milk carton, contain the grease so it doesn't leak. Wait for the grease to cool before pouring it out of the pan. Before washing the pan, wipe out any remaining grease with a paper towel and dispose of it in the garbage.
There's no need to dispose of grease used for deep-frying, because you can reuse it if it's clear. Place a sieve over a clean metal can, an empty plastic jug or a waxed cardboard container, then pour the cooled grease through it to sift out any solids. The container must have a tight-fitting cover and close securely. If the remaining grease isn't cloudy or foamy, store it in the refrigerator in the sealed can for as long as three months. You can often reuse frying oil several times before you must dispose of it. Dispose of the grease if it develops an off odor or flavor.
If you can't reuse grease, recycling is the next best option. Many cities offer grease recycling, but you may have to take it to a dropoff center. Generally, packaging the grease in an old metal can is the preferred recycling method, but check with your recycling center to verify the packaging method they require. Keep the sealed can of grease in your pantry or fridge until it's full, so you don't have to make frequent trips to drop it off.
Although not the best solution, tossing the grease is sometimes the only option. Let the grease cool completely, which can take as long as two hours, then pour it into a leak-proof container. You can even toss in the paper towel you used to wipe the grease from the pan if the whole container is just going to the garbage. Seal the container and place it in a bag before putting it in your garbage can to reduce the chance of a messy leak.