During business hours on weekdays. There may be some amount per day limit, though. Bring lots of government issued ID.
The Post office will cash postal money orders only and they must be at least 2 days old. Picture ID is needed. Postal money orders in the amount of $1000 can be cashed Mon thru Fri til 7:00pm. All other amounts may be cashed daily, if funds are available. (Post office must accumulate cash)
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