If the noise is lower, the AC service may be the cause. Magnetic fields from transformers can cause humming. Mains transformers typically cause an AC magnetic field around them. This magnetic field can be copled to wiring, electronics or signal transformers and cause humming.
Baby oil benefits: ear. Mineral or baby oil is good from treating common ear problems, such as wax build-up. For those that are hard of hearing, we recommend using a few drops of heated baby oil before going to your ear specialist. Then pour the drops in your ear, keeping your head cocked. Hold for a few minutes.
The difference between regular mineral oil and baby oil is that baby oil has a fragrance added to it. If you're sensitive to fragrances I don't suggest baby oil. It can be used to treat mild eczema when corticosteroids are not desirable and also to clean ears ( 2-3 drops). Although mineral oil's main benefit is to sit on top of skin ( as occlusives do to prevent water loss).