Ok let's understand a bit about tarnish first. All silver jewelry tarnishes with time so this is no surprise. Assuming that your silver jewelry is not plated with rhodium or another metal, you can use some conventional procedures to clean it. If the tarnish is not very severe use a recommended lotion or polishing lotion. Polishing fabrics are also available to handle the tarnish. If you have severe tarnish, use a jeweler to get the job done.
Now, if you have gems in the silver jewelry you will need to consider what gems they are. Lapis, turquoise and even bloodstone should not be soaked in water. It is unlikely that emeralds would be set in silver jewelry but if this is the case, detergents, lotions and even soaking can ruin the natural oils in emeralds that are used to treat emeralds.
Check the link below for a detailed report on handling silver tarnish.