If you read the URL "How to Appraise Your Violin" I outline how to use this site to get an approximate value of a violin by comparing it to similar violins in the collection. Once you become familiar with the
concepts that give a violin value you can get an idea of where your violins may fit in.

If it seems to have enough value I then suggest that you take it to a Luthiery and pay to have the violin appraised. Most people do not understand that a lot of the value in more expensive violins depends on what is inside as far as construction compared to what is visible from the outside. Only a luthiery has the tools and the expertise to do this comprehensive evaluation. The luthiery should also be able to give you an estimate on what it would cost to bring your violins to optimum playing and/or selling condition.

So have a look and a read and you should be able to figure things out from there.