Clean the violin bow stick with isopropyl alcohol

[Shadow_]

Hi everyone, I recently heard from a local bow restorer that he sometimes uses isopropyl alcohol to thoroughly clean a violin bow stick. That sounds a bit risky to me - I’m not concerned about varnish since I know many bows don’t really have varnish, but I worry that isopropyl alcohol might dehydrate pernambuco. Wouldn’t that be harmful to the wood, or is this actually a common and safe practice?

Also, are there meaningful pros and cons between isopropyl alcohol and ethanol for this purpose? I heard 99% isopropyl alcohol is much easier to find than 99% ethanol here in the US, though ethanol sounds a bit safer to me.

Thank you very much!

 

[nathan slobodkin]

I use reagent grade ethyl. No adverse issues in the past fifty years.

[Shadow_]

4 minutes ago, nathan slobodkin said:

I use reagent grade ethyl. No adverse issues in the past fifty years.

Is that 99% ethanol or ethanol absolute?

[nathan slobodkin]

1 hour ago, Shadow_ said:

Is that 99% ethanol or ethanol absolute?

Not sure. I have some other stuff which is more exoensive so I'm guessing that is absolute. This stuff says Reagent grade on the jug.

[FiddleDoug]

Most alcohols have some water in them (absorbed from the air). It's very difficult to find 99-100%. Some say 200 proof, but if you read the label, unless they are food grade, they will be denatured with things like Methanol or Isopropanol. Ethanol stabilizes at about 5% water.

I think that a lot of bows are finished with Shellac type finishes, and alcohols will tear those up.

[Woodland]

23 minutes ago, FiddleDoug said:

 

I think that a lot of bows are finished with Shellac type finishes, and alcohols will tear those up.

True, but shellac is easily replaced.

[Shadow_]

2 hours ago, FiddleDoug said:

Most alcohols have some water in them (absorbed from the air). It's very difficult to find 99-100%. Some say 200 proof, but if you read the label, unless they are food grade, they will be denatured with things like Methanol or Isopropanol. Ethanol stabilizes at about 5% water.

I think that a lot of bows are finished with Shellac type finishes, and alcohols will tear those up.

Yeah, but it should be fairly easy to reapply shellac or redo a French polish, right? If alcohol only dissolves the shellac or varnish without harming the wood itself, then it might still be considered relatively safe?

[FiddleDoug]

6 hours ago, Shadow_ said:

Yeah, but it should be fairly easy to reapply shellac or redo a French polish, right? If alcohol only dissolves the shellac or varnish without harming the wood itself, then it might still be considered relatively safe?

Yes, I was taught to clean and french polish bows when they come in for a rehair. I don't do rehairs that often, but I follow the teaching (from a real Master at the craft). I mostly put that up to discourage the average player (only) from messing in areas where only skilled people should go.

[Shunyata]

If the purpose is to clean the stick, I use d-limonene to cut the oils and rosin buildup, followed by water to cut the water soluble dirt.

d-limonene powers through rosin and will not harm spirit or oil varnishes.  My prime directive is “do no harm”.

I am an amateur, so take my thoughts for what they are worth.  

(I am the only person with luthier skills within several hours drive.  When people find out you are rehairing your own bows, the word gets around.)

[Shadow_]

3 hours ago, Shunyata said:

If the purpose is to clean the stick, I use d-limonene to cut the oils and rosin buildup, followed by water to cut the water soluble dirt.

d-limonene powers through rosin and will not harm spirit or oil varnishes.  My prime directive is “do no harm”.

I am an amateur, so take my thoughts for what they are worth.  

(I am the only person with luthier skills within several hours drive.  When people find out you are rehairing your own bows, the word gets around.)

Interesting, I've never used or heard anyone else uses d-limonene on bows before

[David Burgess]

Anyone other than a highly-trained professional luthier should never be using alcohol on, or around violins or bows.

[Shunyata]

@Shadow_ d-limonene is a fully non-toxic terpene derived from citrus peels… kind of like turpentine is a terpene derived from pine trees.  You can use it anywhere you would use mineral spirits, but do note that limonene will dissolve some plastics. 
 

You can literally drink the stuff and it is sold as a vitamin supplement.  

[Nicholas Lewis]

I just started d-limonene as well, it works great and smells nice. It did react with one varnish so far out of about 300 student grade instruments, and I’m not sure what was special about that fiddle. 

[Evan Smith]

9 minutes ago, Nick Lewis said:

It did react with one varnish,,, I’m not sure what was special about that fiddle. 

Probably a real Strad.

[David Burgess]

28 minutes ago, Shunyata said:

@Shadow_ d-limonene is a fully non-toxic terpene derived from citrus peels… kind of like turpentine is a terpene derived from pine trees.  You can use it anywhere you would use mineral spirits, but do note that limonene will dissolve some plastics. 
 

Nope, d-limonene, nor terpene derived from trees, nor mineral spirits are non-toxic, but all are probably a lot safer than fentanyl. 

[Brad Dorsey]

I clean bow sticks with hardware store denatured alcohol, whatever that is.  I have never tried rubbing alcohol.

Bows finished with a shellac-based French polish can be safely cleaned with alcohol, because a shellac finish, once it is hardened, is somewhat resistant to alcohol.  (It takes a while to dissolve shellac in alcohol when preparing a French polish solution.). And I always apply a light coat of shellac to bow sticks, after cleaning them, by the French polish method, which renews any that might have been lost in cleaning.

[Shadow_]

10 minutes ago, Brad Dorsey said:

I clean bow sticks with hardware store denatured alcohol, whatever that is.  I have never tried rubbing alcohol.

Bows finished with a shellac-based French polish can be safely cleaned with alcohol, because a shellac finish, once it is hardened, is somewhat resistant to alcohol.  (It takes a while to dissolve shellac in alcohol when preparing a French polish solution.). And I always apply a light coat of shellac to bow sticks, after cleaning them, by the French polish method, which renews any that might have been lost in cleaning.

Thanks Brad! Just curious if have tried using isopropyl alcohol or heard of someone using it? I was wondering if it’s as safe as the ethanol you usually use~

[Shadow_]

46 minutes ago, David Burgess said:

Anyone other than a highly-trained professional luthier should never be using alcohol on, or around violins or bows.

Thanks David for the reminder, I'll definitely only have professional luthiers do that for me if needed

[Nicholas Lewis]

I don’t use IPA much because I don’t like the smell, but in my experience ethanol tends to cut through gunk more effectively. If I remember my chemistry degree that I haven’t used in a while, ethanol would be more polar with the smaller non-polar portion hydrocarbon chain, so that would make it more effective at dissolving rosin. So IPA is probably marginally “safer” but still an alcohol that can potentially cause damage to the finish.

[Shadow_]

9 minutes ago, Nick Lewis said:

I don’t use IPA much because I don’t like the smell, but in my experience ethanol tends to cut through gunk more effectively. If I remember my chemistry degree that I haven’t used in a while, ethanol would be more polar with the smaller non-polar portion hydrocarbon chain, so that would make it more effective at dissolving rosin. So IPA is probably marginally “safer” but still an alcohol that can potentially cause damage to the finish.

Haha, those chemistry memories really take me back... Glad to hear that, at least in theory, IPA isn’t more dangerous on the wood than ethanol.

[chrissweden]

I use denatured alcohol to remove rosin buildup on every bow that I have and had. Never had any issue. It takes a good amount of rubbing to remove French polish. I wouldn't recommend using alcohol (or intentionally do) on German bows with the "thick" varnish. This will disappear.

If the rosin buildup is very thick I use a dull knife to scrape most of it off first.

Your bow might look a bit dull but this can be easily fixed:

When most of the dirt is gone I put some oil (any will do, lineseed or even sunflower.) with some diatomaceous earth on a cloth and rub the stick clean. This gives the best result and a perfectly clean bow.

Attached a before and after.

[Shunyata]

How long did it take to get the background so clean and white?

[nathan slobodkin]

On 9/5/2025 at 12:42 PM, Shunyata said:

If the purpose is to clean the stick, I use d-limonene to cut the oils and rosin buildup, followed by water to cut the water soluble dirt.

d-limonene powers through rosin and will not harm spirit or oil varnishes.  My prime directive is “do no harm”.

I am an amateur, so take my thoughts for what they are worth.  

(I am the only person with luthier skills within several hours drive.  When people find out you are rehairing your own bows, the word gets around.)

I have heard other people say limonene works for them but in my experience it doesnt do too much to remove rosin and on some varnishes leaves a gummy mess. I would be interested to hear about how others use it.

On bows I have only once seen a finish which was damaged by alcohol. Most bows have a thin French polish finish which will not be damaged by alcohol as long as you dont leave it sitting on the surface. A fast wipe with an alcohol dampened piece of paper towel can remove even fairly thick rosin build up and polish the underlying shellac at the same time.