Dynamic web session clean-up

A "sign-off" cookie is generated and stored upon initiation of a web session between a client and a web application executing on a server. The sign-off cookie preferably comprises both an identifier for the session (a "session ID") together with an identifier (such as a URL) for a sign-off resource (associated with a sign-off mechanism) that can be used to clean-up the web session following its termination. The sign-off cookie may be returned to the client and/or retained within a proxy. Upon termination of the web session, the URL in the sign-off cookie is used to initiate a request to the sign-off mechanism to clean-up the web session. This approach provides for dynamic web session clean-up without requiring any pre-configuration of the sign-off mechanism.