Yes you can deduct the Museum Membership Fees as long as they are under the 501(3)c  guidelines to accept donations giving you the donor the benefit of deducting the donation at tax time.

• Turbo Tax Program- Deluxe, Premier & Home & Business these programs search 350+ tax deductions and credits using form 1040 & Schedule A.
• The IRS requires proof of all cash donations big or small: a canceled check,statement or receipt from receiving organizations suffices. 
• Write down dates , amounts and canceled check numbers, because if the IRS does an audit, they want proof of donation.
  

You can deduct your contributions only if you make them to a qualified organization. Most organizations, other than churches and governments, must apply to the IRS to become a qualified organization.

How to check whether an organization can receive deductible charitable contributions.   You can ask any organization whether it is a qualified organization, and most will be able to tell you. Or go to IRS.gov. Click on “Tools” and then on “Exempt Organizations Select Check” (www.irs.gov/Charities-&-Non-Profits/Exempt-Organizations-Select-Check). This online tool will enable you to search for qualified organizations.

Here is the IRS link to Tax Information for Private Foundations:                                                                   http://www.irs.gov/Charities-&-Non-Profits/Private-Foundations