Based on Randy's proposal:
inform owner of dangling reference. wait a week. inform again. wait a month. inform again. wait a week. remove dangling reference. wait a month to see if anything has broken enough to get the attention of folk who do not respond to email. reassign AS number.
In my point of view, it is enough to inform once. Members have to update their information, members have to be contactable by e-mail.
So: 1. Inform owner about its wrong objects (only once). 2. If an owner doesn't clean up its objects, RIPE NCC should be able to clean up by itself after a month. 3. Re-assign AS numbers after two month.
I agree vith Olaf : - inform once - clean up after a month - re-assign after two months. WBR, Dmitry Menzulskiy OJSC "VimpelCom" Moscwo, Russia