[rules-users] Undeploy problem with Tomcat

I'm deploying a web application with drools 5.0 on Tomcat 6. Several jars remain "locked" on the file system after I undeploy the application. The jars are "drools-compiler.jar" and "drools-core.jar". I am also using a RuleFlow and that file remains locked on the filesystem when undeploying the application as well. I'm assuming that this is a ClassLoader issue or some other unreleased resource by Drools. My question is, has anybody experienced this issue before and how can it be resolved? I'm use dispose() on the KnowledgeSession each time but I never perform any cleanup of the KnowledgeBase. Is that necessary? I also have tried each method of adding rules/rule flows to the KnowledgeBase (File, URL, ClassPathResource) and each type has the same locking issue. Thomas Carolan