Dirty bows (To re-hair or not?)
If you google the above question you will get 100 replies all contradicting one another! In point of fact the time to re-hair is simply when the number of hairs on the bow are reduced significantly due to the passage of time. Professionals will re-hair possibly every 6 months, whilst others (so I read) go on for 5 years. This latter I suspect is a bit extreme because with a reasonable amount of practicing and playing, the bow should be ready for a re-hair in 12 to 18 months.
The second reason that I am often given for a re-hair is that the bow hair is dirty and discoloured. This can be for many reasons but generally the frog end gets very gungy with accumulated dirt, sweat and body oils. If the entire bow is dirty (which believe me I have seen!) the only answer, apart from a re-hair, is to chemically clean up the bow and re-rosin. Some folk even do this if they are changing or using a new rosin.
From time to time (somewhat controversially) it is advocated that you wash the bow hair in a similar fashion to washing your own hair. Now this does not make sense to me. If it was pure horse hair then fair enough – exhibition animals get their tails washed regularly. The difficulty is that the hair on your bow is caked with old rosin, dirt and may be various oily substances which are unlikely to be washed out by ordinary detergents! So, what to do? There are commercial bow hair cleaners available and we would recommend the Gewa Old Master cleaner but you could also use de-natured alcohol which will dissolve the impacted rosin!
There has been much discussion as to what alcohol to use, but the main point is to avoid splashing the stick of the bow as alcohol can affect the varnish and even strip it. Isopropyl alcohol can usually be got from a chemist shop, but failing that use anything, but just be chary of the bow stick. In extreme case the frog can be gently unscrewed and the whole horse hair rinsed out in a bowl. This, however, is seldom necessary. Rather just soak a very clean micro cloth with spirits and squeeze it out so that it is damp but not dripping. Tension the bow with the hair facing downward. With the damp cloth between thumb and forefinger, just slide it along over both the bow hair surfaces. The area closest to the thumb grip will usually be the worst, so concentrate there.
Once cleaned to your satisfaction let the hair dry thoroughly. You may need to gently run a dry clean cloth over the surfaces to free any hairs that are stuck together. Re-rosin carefully while sighting down the surface of the hair. You will notice dark and light patches. Once the surface is universally white throughout the length of the bow, you are good to go!
