Sweat stains on Gibson mandola back

[Trevski]

In the very hot weather we've been having in london, England, on two or three occasions, the back of my H4 mandola has suffered stains…caused either by heat or moisture(sweat). Two questions: how do I remove the stains (although they do gradually fade) and secondly, hows do I prevent repetition. It seems that the protective nitro cellulose lacquer has been worn away over the past 90+ years…Can anybody help? Advise? Thanks…

[CES]

Coming from the southeastern USA (South Carolina initially, with a lot of time spent on the coast, and now Charlotte, NC), where our summer temps reach the mid to upper 90s with a lot of humidity routinely, especially in July and August, I feel your pain. I wouldn't try to remove the stains, per se, just let them fade. It may be worthwhile to get a tone guard to keep the back off your body for this purpose. Most of us just live with the sweat, but I'm also am not playing a 90 year old Gibson Mandola .

Honestly, I have a "beater" or two that I'll take outside in the summer, but I usually keep my better instruments inside in the air conditioning and humidity controlled environment. Not always, but I'd rather sweat stain my Eastman than my Collings. Good luck! I was in Germany and France a couple of weeks ago, and those upper 80s/low 90s temps were working on folks, especially those without functional A/C...

[Timbofood]

Something doesn't sound right, I was not aware that nitro cellulose lacquer was used then. I think it's much more likely that it's varnish which is softening a little in the heat and humidity, the salt in the sweat will dissolve with a little water on a cotton ball but, the after effect may not be worth the issues. Can you post a picture or doesn't the stain show very well.
I would venture that a little finish restoration by a qualified luthier might significantly reduce further damage, more learned folk than I will offer more well educated answers.

[MikeEdgerton]

You could give it a good coat of wax now and then. Find something that doesn't have silicone in it like a paste wax and don't do it while the stains are visible or it may lock them in. It sounds to me like they go away when the wood dries out.

The other thing to try might be a Tonegard. Then your body doesn't come into contact with the back of the instrument.

[Br1ck]

If you have significant finish loss down to bare wood, I'd have a french polish overcoat applied by someone who does restorations. I do not like bare wood. It needs some protection.

[Ivan Kelsall]

If it's down to bare wood,then maybe a Tru oil finish could seal it. If it's just a bit worn,then a good polishing with Bees wax could do the trick. But i'd have a professional luthier take a look at it. Absorbing any moisture,even for a short period,will cause a permanent blemish over time,
Ivan

[Tobin]

The other thing to try might be a Tonegard. Then your body doesn't come into contact with the back of the instrument.

I started to post the same advice, but since this is an H4 mandola which would require a custom ToneGard, and the OP is in the UK where apparently ToneGards are not easily procured, that might be a tall order.

[MikeEdgerton]

I'm not sure. By now Tony has to have produced a few of them, they might be a special order but it's an answer.

[dan in va]

Lewis Fiddlebrite is a rosin remover and polish. It's safe on varnishes and lacquer, and have used it on fiddles, varnished mandolins and Martin guitars. So far it's worked when everything else i've tried has failed miserably. It even romoved dried blood and interstitial fluid from a cut on my picking arm. It may take some rubbing and a few applications, but so far has been amazing.

[Ivan Kelsall]

From dan in va - " Lewis Fiddlebrite" ???. That's a name to remember the next time i book a table for lunch ,
Ivan