This script will remove an acl from all objects in the Servers, Jobs, Depot, Components and Component Templates workspaces. For example, to remove the Everyone.Read permission from all existing objects. This does not remove permissions from folders and smart groups, only objects like blpackages, jobs, servers.
To run this script you must establish creds as a user w/ permissions to modify ACLs on all objects (eg RBACAdmins) and then call the script:
blcred cred -acquire -profile <profile> -username <username>
nsh remove_acls.nsh <profile> <role> <roleToRemove> <auth>
So for example, to remove Everyone.Read from all objects as RBACAdmins:RBACAdmin run:
blcred cred -acquire defaultProfile -username RBACAdmin
nsh remove_acls.nsh defaultProfile RBACAdmins Everyone Read
I've run this in a testing environment, your mileage may vary.