A good pair of binoculars is a precision optical instrument and should be treated that way. They are also produced for the mass market and therefore relatively robust, so that you can have many years of enjoyment with them with a little care.
You should avoid collisions and bumps, so that the tubes and prisms will not come out of alignment. Keep the binoculars in the protective case (if you have one) when it is not used. Padded bags or small cases provide good protection.
The dust caps are also not for decoration, but useful and necessary because they protect the lens from dust and scratches. You should never touch the glass surfaces with your bare hands. Nothing more is really necessary to maintain the good performance of your binoculars.
However, if some dust should get on the optics, it‘s usually better to do nothing. A little dust on the lenses hardly affects the image quality, while cleaning can easily cause scratches in the coating – dust can contain among other things very hard silicates. These scratches can easily cause annoying reflections.
If cleaning is unavoidable (e.g. if there are fingerprints which can attack the coating), you should at first remove most of the dirt with a soft camels hair brush or with compressed air, as they are offered also for cleaning camera lenses in photographic stores. With compressed air a little more safety distance should be maintained than specified by the manufacturer to ensure that no contaminants from the can of compressed air can sandblast the lens.
You can remove deposits from the lenses with a mixture of isopropanol (25%) and distilled water (75%) or a cleaning solution such as Optical Wonder of Baader Planetarium by soaking a cotton ball with it and then moving it without any pressure over the lens. You rotate the cotton ball in the direction in which you engage it – this ensures that no dirt can get between the cotton and the lens.
However, absolute cleanliness never can be achieve and conserved. You should only clean binoculars when it is necessary, and work carefully – many an amateur already has removed or damaged the coatings when polishing his lenses.
PROPER USAGE OF BINOCULARS WITH SKY
Binoculars with more than ten times magnification usually are impossible to use without a tripod. However, you can also hold larger binoculars some time surprisingly steady, if you do not hold them as usual in the middle, but grab them instead just behind the front lens and let the eyecups rest below your eyes. If you support the elbow in addition on a pillar or the roof of a car, shorter observations with high magnification are possible even without a tripod.
To find an object, you must first of all get an overview of the sky – where is your target and what do see in the binoculars? The usual way to find an object is star hopping. You start at a distinctive, bright star or star pattern that you can easily find, and move step by step over fainter stars toward your target.
Inconspicuous, faint objects will not immediately jump into your eye. There are two tricks that may help. A slight wobbling with the binoculars can help because our eye is optimized for the observation of moving things. If a weak spot dances through the field of view, sometimes you can perceive it better. Normally, however, you should hold the binoculars as steady as possible.