I bought a cool ring for a friend. The silver on it has a neat raised pattern and would look much better if it were tarnished down in the crevices of the pattern. Is there a way to do a quick man-made tarnish on silver?
If the manufacturer hasn’t put a sealing coat on top to prevent tarnish, you can put it in a baggie with a hard-boiled egg yolk overnight. If it’s been anti-tarnish coated, you’ll have to get that off first, and for that I got nothin’.
Problem there is that that would tarnish the whole ring, and it seems xanthous just wants to tarnish in-between the raised pattern, which is a might bit tricker.
What if the whole thing is tarnished and then the outside is rubbed with a tarnish remover. A lint free cotton cloth should get to much into the detail.
You tarnish the whole ring, then only un-tarnish the top by using a wipe or something that won’t reach into the crevices
Interesting (OK, maybe only to me. 
) What is it about the egg that causes this?
Sulfur containing chemicals are the best - Hydrogen Sulphide is ace at tarnishing silver. I grew up in a geothermal zone in NZ and the silver was always tarnished, no matter what my mother did. I guess the boiled egg yolk gives off plenty - egg yolks are rich in these sorts of compounds, thus the “rotten egg” smell of H2S.
Si
Chlorine bleach will also tarnish silver quickly.
As does vinegar. But the above suggestions are right. A brief exposure to a tarnishing agent, followed by a rubdown of the raised design will give the design much greater visibility.
I used to wear a silver ring a long time ago but I stopped because whenever I used betadine at work my ring would get instantly tarnished. Betadine is a weak iodine solution, about 1% povidone iodine. Perhaps you could just put some on a Q-tip and rub it along the crevices. But it does tarnish very darkly.
And it doesn’t even need to be particularly strong. The fairly low concentration that’s used for sanitizing dishes (and left on the dishes as they dry) is enough to turn my ring nearly black after a couple hours of washing dishes.
Sounds easy enough, but the ring I want to tarnish also has a large baroque pearl. Will he natural pearl surface be harmed by the yolk fumes? Thanks much…
Probably not, or at least far, far less than any of the other suggestions. Pearls are chemically fragile compared to gemstones and you’re right to worry about it. But I’d say the egg yolk idea will work and be safe for the oyster poop. 
Oyster pus? Since the pearl is made up of nacre deposited in reaction to an irritant, rather than being the end product of the oyster’s digestive processes.
The proper term for tarnish-I-actually-like-being-there is patina. Patina is also the term to use when referring to other metals.
You could google “how to apply patina to sterling silver”.
As somebody that does antique restoration you make me want to weep. People pay me to get rid of patina. 
Not foolproof but wrap the pearl in blue painters tape to sheild it from the brunt of exposure if you do try iodine or something. I love blue painters tape for masking off stuff because it doesn’t leave any gum behind and is gentle on what it sticks to.