Can you tell us about these cameos, are they of value and how do we take care of them?

by Linda R
(Surprise, Az. U.S.)

My husband's grandmother passed in 1992 and the age of 97, she was born in Sweden, moved to the U.S., and also traveled around the world more than once. We are going through my mother-in-laws estate in which we came across some old jewelry and we would like to get an idea of the value.

They seem to be set in silver and on the brooch/pendant looks like a 58 or 5B. Should these be oiled?
Thank you