First of all, you should stay updated with the news about different museums in your area. The organisers of different museums always keep on releasing the news about the new arrivals and events. It will help you in getting information about the promotional activities of museums in which free passes are usually offered to visitors.
Many museums want to grab attention of people towards a new arrival and they organise events in order to make entertain people. They usually offer free and discounted passes to a certain number of people in order to increase the strength of visitors.
Always read the newspapers and art magazines on weekends in which you will find all types of news related to museums. Try to find out the schedule of upcoming events because many museums offer free passes for families especially on the opening day of the event.
Local libraries also play a vital role in providing free museum passes to their members. If you are a member of a local library, then ask the librarian if there is any upcoming event at the museum. Usually libraries get free passes of museums and offer these passes to their registered members.
Many museums offer free passes to people for promotional purpose because offering free passes is the best way to grab attention of people living in that particular area. Make use of these offers and enjoy a day at museum with your family.
You should contact to the help desk or administration of the museums or visit their websites in order to learn if any of these museums offers free passes for any particular day or event.