There are several safe and responsible ways to dispose of used vegetable oil:

1. Reuse it: If the oil was used for foods like vegetables or potatoes, it can be used again several times. However, its best not to reuse oil that was used to cook meat or fish repeatedly.

2. Pour it out: Once the oil has cooled, pour it into a tightly sealable container and throw it in the trash. Freezing the oil before disposal can make it easier to handle and prevent spills.

3. Recycle it: Check with your local recycling center or waste management company to see if they accept used cooking oil. If so, use an empty gallon milk jug to collect the oil and, once full, recycle it.

4. Convert it into biodiesel: Leftover oil can be turned into biodiesel, which is a desirable substitute for petroleum because it is supposedly less damaging to the environment and emits less harmful greenhouse gases when turned into fuel for tractors, motorcycles, and more.

5. Compost it or use it to kill weeds: Vegetable oils, such as canola or olive oil, are compostable in small quantities. Oil can also be used to kill weeds when combined with water to spray on infested plants.

Its important to never pour used oil down the drain or toilet, as it can cause serious pollution and clog pipes. Used oil can contain contaminants that are harmful to the environment and human health, such as lead, magnesium, copper, and arsenic.