Let your Do it Best® store help you keep the cool breeze coming. With the air that moves through a box fan comes dust, pollen and animal hair. It's important that you clean the fan motor at the start of the summer and periodically thereafter. The only tools you need are a shop vacuum and a screwdriver.
First, remove the grilles and vacuum them.
Next, wipe dust off the fan blades. If the blades are greasy, use an ammoniated cleaner like Windex. Don't use petroleum-based solvents or cleaners to remove grease in the presence of an electric motor.
After you've cleaned the blades, use the shop vacuum equipped with a crevice tool to suck dust out of the motor. Air enters at the back of the motor, so that's where most of the dirt will accumulate. Insert the tool into the air holes on the back of the motor case. The motor is clean when you can look through the air holes and see daylight at the other end.
The last step is to lubricate the motor with 10 to 20 drops of 3-in-1 oil. The oil holes are usually on the top of the motor case or in a dimple on the motor's front or back. If there are no oil holes, it means the motor is permanently lubricated and does not require oiling.