If you were to buy yourself a little piece of platinum wire, not too expensive, as it's only needed in a single piece of some of a gauge stiff enough to take up a bit of a solid in distilled water, to apply to a torch flame, borax will give a green colouration to the flame, lighter green than copper and not the apple green of barium ions.
The platinum is used because it's very unreactive and also heat-resistant, won't contaminate the flame colour.
Take a bit up on the tip of the wire, insert into flame. The sodium in borax will add the bright orange sodium D-line characteristic of the emission spectrum of Na, colour of sodium lamp street lighting. But there'll be a green introduction, leaf green I'd call it, a bright leaf green, then that shows that boron is present.
And you can buy small but damn powerful samarium-cobalt magnets online for not too much.
An alternative would be the core, if sliced in half through and through, ought to fail to react to hydrogen sulfide gas after moistening with distilled or de-ionized water (available dirt cheap in auto stores for topping up lead-acid batteries). If you need to know how to make the gas, just let me know, but be aware it's something only to perform OUTSIDE. And only if comfortable in handling it, because H2S is both highly toxic (disrupts the electron transport chain like cyanide gas does, and is similarly fast acting and deadly in sufficient concentration) and a sneaky, insidious little bastard. Smells foul, gives rotten eggs the characteristic eggy stink, but also, and this is what gets people where the concentration isn't 'one breath and you are dead', the stink is obvious, people then note it has vanished, leaving them to believe that the hydrogen sulfide is no longer present, since the smell is gone.
It hasn't gone anywhere. It paralyzes the olfactory nerve (temporarily, assuming of course that the individual hasn't been fatally poisoned, as dead people aren't known for their smelling. Not with their noses, at any rate. They are quite good at it with the rest of their putrid bloated rotting guts being readied to blow out of their ruptured stomachs as corpse-gas builds up and bursts them open in hot weather
. The loss of sense of smell with dead people though, it tends to be rather long term.....)
So the H2S, still present, has just put on it's ninja hat and pulled a vanishing act, but it's there, alright, it's just stalking it's prey, the sneaky little bastard.
H2S causes silver to blacken due to a surface layer of silver sulfide forming, this has a dark colour, a fair proportion of the tarnish silver takes on in jewellery is due to sulfidation thanks to sulfur-containing amino acids in proteins from skin secretions, like cystine, cysteine, methionine for example.
Never tried using say, a solution of methionine or cyst(e)ine in distilled water as the sodium salt of the amino-acid to solubilize it, although it might work to tarnish silver without needing hydrogen sulfide itself.
The samarium-cobalt rare earth magnets are cheap, and for their size the magnetic field is remarkably powerful, even in a rod about as wide as a BB pellet and 2cm long. Platinum wire option too won't cost that much, and it will be reusable, just the one little piece of stiff wire an inch long or so is fine.
I've used the H2S test quite a number of times, after dumpster diving, especially after that time I found a big haul of silver, much antique and readily identifiable visually without testing, but some bright shiny metal that I suspected. So had to whip out the labware and start testing.
Also, one other way to do it, to test silver itself, is that it will dissolve in dilute nitric acid, and if you want any, I could spare some easiiy, and make up a batch for you. Silver, once dissolved to produce aqueous silver nitrate, is characteristic in that upon the addition of chloride salts, such as table salt, the corresponding metal nitrate is formed, the silver stealing the halogen atom, to form silver chloride, a white solid substance which is pretty much totally insoluble in H2O, and so, precipitates out when table salt is added to silver nitrate, leaving aqueous sodium nitrate dissolved, whilst the solid precipitate crashing out is diagnostic of silver.
Silver chloride, in common with other halides that behave the same in this reaction, is photosensitive, darkening with exposure to sunlight, due to it's reacting to form elemetal silver in finely divided state, which looks black. This was used, with silver iodide impregnated stock, in some early black and white/greyscale photographic processes, the camera working by selective exposure of some parts but not others to varying levels of light, darkening the hit portions, as silver forms, and then the rest processed to remove the silver salts which aren't developed in the darkroom.
Silver iodide can be formed instead, by using NaI or KI (cheap, if you wanted a bit of HNO3 for testing, I could spare a bit of an alkali metal iodide to use for the same process. The insoluble precipitate being diagnostic, and if iron chloride (ferric chloride) forms, it's soluble in water and it has a dark green colour in solution.)
