What devices have you found useful when inspecting your stylii for cleanliness?

A loop is the most obvious. The best lens makers are Schneider-Kreutznach, Zeiss and Leica.

Thanks everybody and especially @elliottbnewcombjr for the very informative pictures.  I am going to go for something like that small LED-lit magnifying mirror and a BelOMO loupe.

Only problem is that I live Down Under.  The Australian website selling BelOMO has stopped carrying them, offered me a Russian one instead.  They think that Amazon may be able to oblige.  The US store's website has them as "out of stock' but apparently some have just come in.  Next issue - they only have facilities to ship to the US.  But in a few weeks' time that should change!  Down here, we just pop things in the mail.

As a trading nation, Australia does not have tariffs, and the local 10% goods and services tax is not normally charged on small imported items so we positively encourage imports.  In exchange for our copious supplies of iron ore, coal and gas, I'm afraid.

Have not been able to find a suitable mirror yet, either!  But as they say, I am looking into it

@richardbrand I would try B&H in New York City for new or KEH in Georgia for used. Sorry for misspelling loupe.

@goofyfoot Spelling forgiven! I am sure it was your spell-checker :-)

I have been getting offers from B&H every week! Took me a while to realise they were once Bell and Howell of movie equipment fame.

It also took me a while to realise that most loupes are used for jewelry or inspecting creepy-crawlies. Australia is not short of jem-stones, or nasty biters. It seemed silly to order from New York so I searched locally.

Because I could not source BelOMO loupes, I have gone upmarket and ordered a Zeiss Optics D4 10X loupe. I could get one in town (Sydney) for a tad over A$340, which is about what my stylus is worth, but I found one on-line for well under half that from China, including our 10% gst. Hope it is the real thing!

This is a nostalgia trip for me, as I am restoring my Dad’s Garrard 301. He lent me the first camera I ever used, which was a Leica film camera with a fixed 50-mm Zeiss lens. He took award winning black and white photos on it, but I could never remember to set all the eight manual controls needed for proper photography. Nothing digital about it, or even electrical. Bit like vinyl, really.

@richardbrand Yes, hopefully that Zeiss Loupe from China is either real or a really good fake. I have a T* Zeiss monocular and it’s as clear as you could ever hope for. Personally, I gave up 35mm a long time ago. I now use a Toyo 45 A 4X5 field camera that is of course totally manual. I have Schneider lenses and for the exposure reading, I use a Pentax Zone 5 spot meter. I’ve gone to shooting Fujichrome transparency and then I send it to CRC in New York for processing and high resolution scanning. I believe some of those Leica digital cameras cost about what a Hasselblad digital back would cost. Anyway, I think we got off the topic of audio but if that Leica loupe isn’t helpful, you could spend even more money on a large format camera and use it against the glass view finder.