Neem oil: If you have been wondering how to kill mosquitoes, try neem oil as it acts as a great indoor mosquito-repellent. A study published in the Journal of the American Mosquito Control Association {1} found that mixing neem oil is an effective way to keep mosquitoes at bay. Being a potent antibacterial, anti-fungal, antiviral and anti-protozoal agent, neem lends your skin a particular smell that wards off mosquitoes. To make an effective insecticide mix neem oil and coconut oil in equal portions and rub it on your body (all exposed parts). This will protect you from mosquito bites for at least eight hours. Here are 5 ways to save your baby from mosquito bites.