It will all depend on what kind of old jewelry you have. In general, you can roughly estimate their value and in this I have helped the article on this site
https://www.pacificpreciousmetals.com/blog/selling-your-gold-jewelry I thus not bad so earned on the jewelry which I inherited. Sometimes even a silver ring from a famous brand can be more expensive than a regular gold one. You can read more in detail by clicking on the link that I have discounted above.