I will soon be getting my degree and wanted to do a personal research on a matter. The thing is, the museum is abroad and so I intended to email them to ask for permission. But in case someone can give a heads up as to what answer to expect. My degree will also include archaeology and history of art, as in my country (Greece) we do all three as one course and later on choose which we prefer and focus on that. The items in question are mostly old letters and/or other personal papers of a physicist (if that makes any differece). Thank you in advance!!
The policy will vary by institution and country - in my experience, many if not most places are willing to allow any researcher access. Some places are more concerned about credentials though - they might want confirmation that you are affiliated to a university, for instance, or to know exactly what you want to look at and why. Without knowing where you're going, it's difficult to be more precise - but the easiest thing to do is simply to contact them directly.
Each museum (should) have a formal policy, which (should) be included in their website. Depending on what you want to see (and the value of it) you may need to provide resumes and references.