They used to make line for fishing out of horse tail hair, back in the days before nylon and etc had been invented.  My wife keeps any hair from my bows because it apparently has some specific uses in mending and uhh.. textile stuff.  She's the one in our family that knows cloth, thread, yarn and fibers and etc, not me.  When I cut off all the hair from one of my "free" Chinese bows she was delighted to get a whole hank at almost full length.  I rarely lose bow hairs so far.  I've only lost maybe six from my "good" bow in the three months or so that I have played it, and half of those were when I was working on the "Bile them cabbages" piece, due to them getting snagged on something when I set the bow down.

Like I said, she's the person that knows fibers in the household.  According to her most natural animal fibers like hair (wool for example) and silk are best washed in something mildly acidic or at least not basic/alkaline.  Most soaps are at least a bit alkaline because they are usually made with lye or equivalent to turn grease into soap.  A mild acid rinse afterwards could restore the hair to the proper mildly acidic pH. 

But that is before it is put on a bow, and none of that would help with getting the rosin out of the hair. 

Alcohol is the better choice because it does have a neutral pH.  Ideal for the hair would be if it was mildly acidic, but alcohol would be kinder to it than soap, which is usually basic/alkaline pH.  The 70% concentration you suggest also has enough water in it that it probably won't dry the hair out as much as a higher proof might. 

However, taking your alcohol method plus the "best if kept slightly acidic" idea does suggest something that might be worth a try.  Lemon juice will naturally lighten the color of hair a little, and it is acidic. but would be too strong to use undiluted.   I could calculate what amounts more precisely, but the juice squeezed from half a lemon mixed with a glass of water would probably be close enough.  Use that to dampen a bit of cloth and wipe down the bow hairs after cleaning the rosin off them with alcohol and it theoretically would make sure the hair is at something like the optimal pH, it would remove any soap traces that might be left from the commercial process of preparing the hair, and it might even make it a tiny bit whiter/prettier over time.  I wouldn't actually soak the hair in it because too much moisture might manage to get into the frog or head joint of the wood, but wiping it with a dampened cloth should be ok I would think?

What to do with the rest of the glass?  I dunno, maybe stir in a spoon of sugar and call it lemonade?  LOL

Also, I don't know about bow mites specifically, but lemon is supposed to be a mild insect repellent. 

Just an idea and it is untested, but it might be worth considering trying adding it to your alcohol method if anyone is feeling adventurous.

I wouldn't use the corn starch trick on bow hair because it could cause the same problem as the fine rosin dust we are trying to get rid of with cleaning the hair in the first place. 

Lemon extract is usually lemon oil in alcohol, unless you mean the bottled lemon juice they make from concentrate.  The acidity of the bottled (or in a little plastic lemon) stuff should be about the same as fresh lemon juice, I think.

@Oliver:  I don't really know either.  I'm still way too much of a noob to know about long-term care.  With the lack of troubles I've seen from rosin and the fact that bow hairs break occasionally, I would guess that I may need the bow rehaired before it might actually *need* a cleaning like we are talking about here.  And considering my "good" bow is a 20$ student model, I'd probably count more on replacing the bow and then trying rehairing it as a project.

I can see situations where cleaning might be necessary.  If something bad happened to a bow you like and something got on the hair, it might be better to try cleaning it than just assuming it had to be rehaired.  Or I have heard (but never seen myself yet, 'cause I'm a noob) that over time the rosin can somehow solidify or something and make the bow hairs more of a solid smooth band than a band made up a parellel hairs, so it might not hold rosin and make a tone right anymore.

So I don't know for a fact, but considering some more experienced folks seem to consider it important, I figure eventually it is.  I can understand the idea as a process, though, and that is what I am going on with my thoughts in this thread, rather than actual experience.