You need to look at the amount indicated on the website. If less than $150, it is probably not worth the effort to figure it out. If more, there is no way of knowing how much more without processing the claim. If the claim is not processed, the state eventually keeps the money.
In estate administrations, our office processes dozens of unclaimed funds requests. I have never processed one with a "great-great" claimant, so I am not certain what UCF does ... if they will pay out to a single claimant or if they will insist on processing the entire family tree including your 3 aunts and/or uncles and their children and your siblings, if any.
The best way to find out is to submit a claim. If you wish to do so on behalf of all your grandmothers heirs, you could do so. Or you can just submit it in your own name and see what happens.
You will need to attach a copy of your grandmother's will, the one that was filed in Probate Court with the filing stamp on it. Be prepared for the fact that they will probably ask for the names and addresses of all your grandmother's other heirs, and perhaps copies of the Wills of your aunts/uncles.
Hopefully, there is enough money involved to justify the effort. And if you must share it with your aunts, uncles, cousins and siblings, they will be appreciative of your work.
Mr. Huddleston is an Ohio-Certified Specialist in Estate Planning, Trust & Probate Law, with offices in Columbus and Dayton, serving client families and private business owners throughout Ohio. He may be contacted directly by phone toll-free at 888.488.7878 or by email CLH@HUDDLAW.COM. Mr. Huddleston responds to Avvo questions as a public service to help educate and provide general guidance to questioners, but his responses are not legal advice and do not create an attorney-client relationship.