How to Clean Your Bow Hair
Cleaning vs. Replacing Bow Hair
Bow hair becomes dirty over time, picking up dust and oil, which take away from your bow's ability to articulate and grab the strings, and substantially diminishes the quality of its sustained tone, as well. If the bow has lost much hair or if it can no longer be tightened sufficiently to play, then it is time for a re-hair. But, if the hair is simply dirty, there is no need to replace it. It can easily be cleaned.
Now, I will just note here that some players rail against the idea of cleaning bow hair, insisting that it will either damage the hair, or that any hair old enough to need cleaning is old enough to need replacing. Yes, there is some very fine, very fresh, Siberian stallion hair favored by some elite players (though you need to know where to get it, as it's not widely available). And, this hair does have desirable performance characteristics which diminish over a fairly short time. Those players (and you know who you are) tend to re-hair their bows often - both to maintain those desirable characteristics, and because such hair tends to stretch quickly and react dramatically to humidity changes, so re-hairing becomes necessary for mechanical reasons rather quickly.
But, if you're not taking pains to seek out extraordinarily fresh hair (and I don't generally recommend doing so for the reasons I just mentioned) then there is no particular need to replace your bow hair simply due to age. The usual high-quality Siberian and Mongolian hair, available from dealers and bow makers across the country, will keep performing well for years, if kept clean. And, I can assure you that cleaning will not damage or detract from your bow hair's performance, no matter what your teacher may tell you. And, you may be surprised how a cleaning can restore the performance, tone, and vitality of your bow.
What You'll Need
You'll need some denatured alcohol, available from your local hardware store. (Careful, it's laced with a poison to deter its use at frat parties, so keep out-of-reach of children.) You'll also need some paper towels (or a clean cotton cloth - i.e. old t-shirt) and a comb.
First, tighten the hair to a bit under regular playing tension - just tight enough to keep the hair off the shaft of the bow.
Next, apply a generous amount of alcohol to the paper towel - fairly wet, but not dripping.
Wrap the paper towel over and under the hair and rub up and down the hair to get it clean. Try not to touch the shaft of the bow while you're doing this. Disclaimer: If you have a particularly fine pernambuco bow, please take it to a professional. With that said, you don't need to worry about damaging or dissolving the varnish on your bow, as you would on your violin, because bows are not varnished. Nothing terrible is going to occur if you happen to brush up against the wood a bit while cleaning the hair. Still, alcohol could temporarily dull the shine of the French polish, slightly, so try to keep the paper towel away from the wood. Another option is to remove the frog from the bow while cleaning, in order to keep the hair completely away from the wood. I don't personally find this necessary, but feel free to do so if it makes you more comfortable.
If the hair is very dirty, it may require several minutes of treatment, in this way, before it shows clean. Add more alcohol and change paper towels as necessary.
Once clean, allow the hair to thoroughly dry. This may take a few hours.
The hair will be clumped together - not good for rosining. So, take out your comb and gently comb it smooth. I use a comb especially designed for the purpose, but a regular old hair comb can do the trick. By placing the comb under the hair, and combing up, away from the wood, you'll avoid scratching the bow. Be gentle, and don't pull too hard. You don't want to break the hair or yank it out of the tip mortise.
Now you have clean hair, but no rosin. Ideally, at this point, you'd want to "prime" by rubbing crushed rosin across and along the hair.
Raw hair is slick and doesn't take rosin well, so priming would help your rosin to adhere quickly and evenly. (With a cloth or piece of leather, repeatedly dab into the rosin and rub it across the hair, then along the hair, on both sides.)
Unfortunately, most players don't have crushed rosin just sitting around the house. But, don't despair. You can just apply your regular rosin, as usual. But, be prepared to rosin for quite a while before the bow is ready to play (perhaps 100 strokes or more). If you do prime, then be sure to add your regular rosin as well, afterwards - 25-50 strokes might be necessary to get the rosin evenly applied. You'll have too much rosin in places, but it will even out, over time. Once settled, you should apply only 3-5 strokes of rosin, each time you play. Add more, as necessary, if the bow doesn't grab. Use less if you see clouds of rosin coming off your strings. (Most students use much too much rosin, which will dampen the tone, not to mention the mess and possible damage to the violin.)
Fresh, High-Quality Rosin
One last note . . . Please don't go to all the trouble of cleaning your bow hair, only to apply old and dried-out rosin to the freshly cleaned hair. Ironically, though teachers tend to rail against cleaning hair, they often fail to encourage their students to replace rosin when needed. For good bow performance, and especially for good tone quality, never use rosin that is more than a few years old. The best recommendation is to replace rosin yearly or as often as you clean/replace your bow hair. And, stay away from the ultra-cheap rosins that sell in the under $5.00 range. A $10.00 - $20.00 investment in a decent cake of rosin can make a world of difference to your performance.