Q&A for How to Reuse Cooking Oil

No, this is not recommended at all. Cooking oil or fat poured down the sink can solidify and clog the pipes, causing you to have to get a plumber. Even if it doesn't clog your pipes, it can join with other oils and fats and clog the civic sewer system. That might not seem like your problem––until your rates go up and local wildlife suffers from poor water quality. Instead, keep aside old jars to pour oil into. Once filled, the jar can be disposed of in your usual trash waste.

Yes but only in small amounts over a long period of time. First, make sure it is just vegetable oil and nothing else (e.g. safflower, sunflower, olive oils, etc.). Second, only add small amounts of oil now and then. If you pour in too much vegetable oil and do so frequently, the compost won't decompose well as the oils will clog it all up. After adding, stir well to ensure it is evenly distributed across the compost.

Yes, you can store vegetable oil slated for reuse at room temperature. Store in an opaque bottle or other container, preferably glass. Keep the stored oil away from direct light in a cool, dark cupboard or pantry. The bottle (or other container) must be sealed during storage. Do not subject to warm temperatures during storage.

No, this is not a good idea. The oil may melt the trash bag and cause the contents to spill out and it may melt other objects in the trash already, potentially releasing toxins in plastic containers, etc. It may also present a fire risk if it mixes with something flammable. In general, wait until the oil has cooled down, then pour it into an unwanted container and dispose of that container in the trash.

Check your recycling program. Some refineries accept cooking oil. There are also recyclers that come around when you're talking gallons of oil from your restaurant. Some auto shops accept cooking oil, too - check with them; many shops still use burners that use this for heat, some like it for the "yard" diesel engines.

Sunflower oil has a smoking temp of 440°F and, as a cooking oil with a high smoking point, it is definitely OK to reuse in this manner.

This depends on your recycling centre. My small town recycling centre accepts very little, but centres in the big city a couple of hours away can even recycle paint and styrofoam! Contact your usual recycling centre to check.