That's going to depend on the information you gathered at the time the money order or teller check was drawn. If you were able to capture name and address information, then you would escheat to the state in the address. If you did not capture that information or the address was foreign then you would escheat to your state of incorporation. Unless you entered into an agreement with the check/money order issuer for them to perform escheatment, it would drive off of your institution's state of incorporation.
Delaware does not require due diligence mailings on most property types, but recently passed legislation requiring it on securities with a value over $250.00.
http://unclaimed-property.keaneco.com/delaware-clarifies-escheatment-of-securitiesDelaware does have an advertising requirement. See the reporting manual for the specifics:
http://revenue.delaware.gov/unprop/handbook12.pdfDue diligence and dormancy periods for items reportable to other jurisdictions would be decided based on the statutes for those states.
Since we are in New Jersey's forum, the NJ regulations are in the following link with the due diligence requirements on page 12.
http://www.unclaimedproperty.nj.gov/pdf/regulations.pdf