Yes.....you can use....it won't harm.

If you feel an insect is fluttering in your ear, just pour any edible oil into your ear to flood it and kill the insect. As this usually happens at night, after the insect has stopped fluttering, just go back to sleep. However, please visit an ENT Surgeon the next morning to remove the insect as well as remove all traces of the oil as if left there could lead to fungal infections in ear!

Hydrogen peroxide is a chemical and best to AVOID using it to clean ears. It can damage ear canal skin and cause inflammation. As a home remedy - If an insect enters the ear best thing to do is to pour baby oil or even clean coconut oil in the ear canal to suffocate and kill the insect. Pouring water may not kill the insect.