F5 Load Balancing and Cisco Routing

Will need a little more clarification about your topology to make a better educated suggestion. I will say that the reason you can't remove the self-ips is that they are being used to connect to your nodes/pool members. If you have L2 connectivity to the networks they live in, the BIG-IP won't let you remove those until they are no longer needed. This can be accomplished by adding additional new self-ips in those networks so you can reclaim what you want, but I can't say if that is prudent without more of an understanding of your topology.