Hide irrelevant SFDC objects and fields from Admin tools?

As a Gainsight administrator, tasks such as report building, using the rules engine and creating custom data spaces are painful because of the insanity of our SFDC data. Over the years, we have accumulated a massive amount of objects, fields and data that is out of date, incomplete, or otherwise not useful. Wading through all of this noise makes it difficult to efficiently perform various administrative functions. Is it possible to hide irrelevant and/or deprecated SFDC fields  so they don't appear in Gainsight at all?