Unfortunately, all too frequently!
You can google the relevant code by searching for "Texas Museum property law", which should find Texas property code, sec. 80.004 for abandoned property.
if the property is from another state, you will need to consult the museum property code for the state of origin. Most states follow a uniform property law, and there is not much variation among states. Typically the differences are in the length of time between when an item is found, and when you can dispose of the item, and the amount of time between attempts to contact the owners. If in doubt, use the more stringent code. Typically, you are required to contact the owners a couple of times in a couple of months. Be prepared to post public notice (newspapers) in the last known city or county of the property owner. If you have no information, you will still need to post public notice in the likely location of the owner.
I am editing to add that a graduate student a few years ago addressed FIC (Found in Collections) issues and best practices, I could not find her thesis link, but there is a similar one here:
http://www.connectingtocollections.org/wp-content/uploads/2017/09/What-is-this_-Found-in-Collection-PowerPoint-Slides.pdfSince that graduate thesis, we have kept affidavits for found in collection items, because every state requires you to maintain these items as loans for a period of seven to fifteen years. (Texas is 15). The affidavit is a simple form with a few key ingredients:
WHAT was found, a photograph or several, including context, and a written verbal description
WHEN it was first found - a specific time, avoid "it's been here since the 1970s", be as specific as possible "I started graduate school in September 1992, and this item was in classroom X at that time."
WHERE in the museum it was found
WHO found it - A signature, a date, a written name.
A number should be assigned to connect the FIC files with the objects, since you may be tracking these items for over a decade.
To this affidavit, you should (must) append records of your attempts to contact the owner. Ideally, such items, like loans, are queried and address at the first of each month as necessary - because whether they have associated information or not, these are legally loans unless you have attendant donor agreements in place.
People will return to claim such things years later, and even several generations later. So you have to document...
best-
Chris Sagebiel
collections manager
Texas Vertebrate Paleontology Collections
The University of Texas
Sent from my phone