As any good student of museology should know, the MA describes disposal as ethical when:
• it is within the framework of a clearly defined collections policy
• it is on the advice of a range of staff (not an individual) and is agreed by the governing body
• it is done with the intention that wherever possible items remain within the public domain
• it is unlikely to damage public trust in museums
• it is likely to increase the public benefit derived from museum collections
• it is communicated openly to stakeholders and the public.*
Points 3 and 6 are often achieved by advertisement in the Museums Journal; in a format somewhat akin to 'classified listings' in the local rag. Though, of course, these items are not 'for sale' in the conventional sense, just free to a good (institutional) home.
Since I first subscribed to the MJ back in 1998 the disposal notices have fascinated me; what weird and wonderful things museums have in their possession (and desperately want to relieve themselves of)!
The new online listings make equally fascinating reading. Got a hankering for back issues of Practical Wireless? Then the Royal Signals Museum can help you out. Need an Edwardian witness box? North Lanarkshire Council will do you a 'deal'. Require a low-tech printing solution? Dover Transport Museum's Arab Press could be just what you're after.
* see - Disposal Toolkit: Guidelines for museums, Museums Association, 2008.