[development] Automatic disabling of comments

[nan wich]

I have seen this done on the web and surely there is a module in Drupal, but 
after half an hour of seraching can't find it. I need to set comments, 
preferably by content type, to disabled or read-only after a certain length of 
time. I don't think it would be hard to write, but I'd hate to re-invent a 
wheel 
if it already exists. Does anyone know of such a module?
 
Nancy
 
Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.