To use a handheld oil dispenser, first ensure it is clean and dry. Fill the dispenser with your choice of oil, such as olive, vegetable, or canola, using a funnel if necessary to avoid spills. Securely close the dispenser to prevent leaks. 
Before using, check the nozzle or spout for any blockages. If the dispenser has a pump mechanism, prime it by pressing the pump a few times until oil flows smoothly. For models with a trigger or squeeze mechanism, ensure it operates freely.
When ready to dispense, hold the dispenser over the target area, such as a pan, salad, or baking dish. Adjust the angle and distance to control the flow and coverage. For a fine mist, hold the dispenser further away; for a concentrated stream, hold it closer. 
If the dispenser has adjustable settings, select the desired spray pattern or flow rate. For even distribution, move the dispenser in a sweeping motion. After use, wipe the nozzle to prevent drips and maintain cleanliness.
Store the dispenser in a cool, dry place, away from direct sunlight to preserve the oil's quality. Regularly clean the dispenser by disassembling it, if possible, and washing with warm, soapy water. Rinse thoroughly and allow it to dry completely before refilling. 
Periodically check for wear and tear, especially in the seals and pump mechanism, to ensure optimal performance.