How to clean violin bow

The same rules apply for cleaning your bow as cleaning your instrument.
It depends also on where you mean, the stick or the frog. If you are talking about the hair, don't do anything, although keep in mind that you are not supposed to touch the hair when you hold the bow. If it is just the frog, unless it is a valuable old bow, you can use some 0000 steel wool and a drop or two of mineral or linseed oil. Don't get any oil on the hair and don't use the steel wool on the bow stick.

You should always be careful when cleaning and polishing an instrument. First of all you always clean an instrument before you polish it. You don't want to polish dirt into the finish. Some cleaners are dangerous to use on some finishes, without trying it first on an inconspicuous spot, like on the side by the chinrest, you won't know how it will react. Most commercial cleaners aren't that effective, keep in mind that violins other than cheap student ones are varnished, this varnish is made up of gums and resins. Cleaners have some sort of solvents in them to break down the dirt; these solvents can also dissolve varnish. I once saw several inches of varnish slide off of a modern Italian violin that was left too close to a rag with alcohol on it. Many professional violin shops use Xylene to clean violins; this is a very dangerous chemical to breath and must be used very carefully. As far as polishing goes, most commercial polishes contain oil - to make things shiny. If there are any open edges or cracks in the instrument, the polish can get into those spaces and make it very difficult to repair. I would recommend that you have the local violin shop do a cleaning and polish. If after it is done, you just use a soft cloth to clean your violin before you put it away each time, that cleaning can last for years. If you are getting lots of rosin dust on your instrument each time you play, you are using too much rosin.

If you want to clean and polish your instrument yourself here are some things to think about.
1. Always check your instrument for open edges and cracks before you polish as doing so may prevent the proper repair of your instrument.
2. If the instrument has a lot of rosin and dirt, you should take it to the violin shop and have it professionally cleaned.
3. Never use any household cleaners or wood polishes on an instrument. Only use specially designed ones for instruments. Never get alcohol near your instrument. Professionals will use Xylene to clean, but it is very bad to breath and can cause cancer, so do it outside and just small amounts on a clean cloth. Start in an inconspicuous spot. Many professionals will use Renaissance Wax to polish; it is similar to a paste automotive wax but has no oils in it.
4. Don’t use a one thing does both polish and cleaner or you will be polishing the dirt into the varnish and it will get trapped and never come off. The longer that rosin sits on the varnished surfaced the more it becomes part of the varnish. Rosin is made from the same material that goes into some varnishes.
5. Use a small amount at a time, gently buffing in small circles in a small area with a clean dry cloth.
6. Once you have a polished instrument, it may be a year or so before you will need to do it again. Just wipe the instrument off with a clean, dry cloth after playing. If you are seeing a lot of rosin dust on your instrument after you play, you are using too much rosin.