Hi BlueMtnCabins,
No, not really. When you say "used" do you mean the custom field has values in it (in some booking or property) or that it's being actively referenced in an email template, legal agreement, etc? I'm guessing they all have values in them, if you go back and look at historical data, so you wouldn't want to delete them. If you compare your email templates and renter agreements to your list of custom field definitions, that would be the best indication of whether they were used now actively.
