Try this with silver instruments.

[bloke]

Personally, I don't own any silver plated instruments. I'm not saying that I'll never own any ever again, but I just don't happen to own any right now and view that finish as a nuisance.
I watched a video a few minutes ago about how chalk or calcium carbonate absorbs moisture and breaking off or cutting little pieces of chalk and putting them in a paper towel in with silver jewelry discourages it from tarnishing.
I'm wondering if any of you might be interested in experimenting with your silver instruments in the same way. You might want to collect up some little Crown Royal bags or find something similar or stitch together little bags of similar very soft material with a drawstring and put several little bags of chalk in with your instrument.
Since most people carry their fragile tubas around in dent bags, I suppose those little bags of chalk would all end up in the same area of a bag, but maybe in a hard case (which almost no one uses) the bags would stay spread out a little bit better. As I type this, I'm wondering if bags that are even thinner than the bags I described above would be more effective in getting moisture to the chalk. Maybe something like little bags made of worn out t-shirts or something like that.
I don't know if this would work, but I'm the only wondering if it would based on the video that I watched. I know about those bags which are supposed to prevent tarnish, but I don't think very many tuba players want to pull their instrument out of a case or bag, and then pull it out of yet another bag.

[MiBrassFS]

3M made and now Hagerty (and some generic brands, etc.) makes treated strips of paper that prevent (slow down at least) tarnish from forming if you keep a few in cases in which silver instruments live. I’ve had good luck with them for decades and always keep them in my cases.

Interesting about chalk. I wonder if there’s some sort of chemical reaction going on similar to the silver strips.

I should also say that I’ve only used ones from 3M. I imagine the ones by Hagerty are similar.

[bloke]

I also read that a whole bunch of insects can't stand chalk, and - if you simply draw a heavy chalk line outside your threshold - it will deter crawling bugs.

bloke "READ it...do not KNOW it"

[Tubeast]

I´m too feebly educated in chemistry to actually shed light on this,
so this post should rather be taken as a nudge to knowledgeable forum members to maybe chime in and help me out.

To my knowledge, silver tarnishes faster with rising sulfur percentage in air, because it´s sulfur that forms silver sulfites on silver objects, which is what silver tarnish is.
So if along with moisture you capture sulfur molecules in those chalk bags, that´s where the benefit should originate.

You might get even better results if you use those silicate bags that will come with most professional parcel deliveries.
Those do the job and MUST be cheaper to produce than bags of chalk, otherwise chalk would be what those bags contain.

The white granulate you put in your cat´s litter box should do a good dehydrating job, too, and may be even more readily available than chalk. (You might prefer using granulate from the bag rather than the litter box, though )

[bloke]

I haven't bought chalk since my rulers suddenly printed 10 - 15 trillion dollars of money that neither supported goods nor services, but - before that time - chalk was pretty darn cheap. (I buy it every once in a while to coat the teeth of files in order to prevent filed metal from embedding itself in those teeth.)

I do like the silica gel packs, and particularly how considerate their manufacturers are of me by advising me to not eat them - printed on the outsides of each one.

I suspect that lacquer works better than either chalk or silica gel.