These are the steps we have used to remove the old server UUIDs from the apigee edge.

Remove from Management server :-

steps:

1. Unregister servers from the organization's environments on Management Server:

curl -v -X POST http://localhost:8080/v1/o/<ORG_NAME>/environments/<ENV_NAME>/servers -d "uuid=<UUID>&region=<DC_NAME>&pod=<GATEWAY_NAME>&action=remove" -u <<systemadminuserid>>

2. Unregister server’s type on Management Server:

curl http://localhost:8080/v1/servers -v -X POST -d "type=<TYPE_NAME>&region=<DC_NAME>&pod=<GATEWAY_NAME>&uuid=<UUID>&action=remove" -u <<systemadminuserid>>	

3. Delete RMP on Management Server:

curl -v -X DELETE "http://localhost:8080/v1/servers/<UUID>" -u <<systemadminuserid>>

Verification:
 
1. verify Orphan UUID is not in registration

/<<install directory>>/apigee4/contrib/registration-overview.sh -p <pwd> <DC_NAME> <GATEWAY_NAME>

Now remove it from zookeeper:-

Steps:
1. Get the zookeeper tree

/<<install directory>>/apigee4/contrib/zk-tree.sh > tree-before.txt

2. Go to the zkCli.sh on zookeeper node and run /<<install directory>>/apigee4/share/zookeeper/bin/zkCli.sh

2. At the zkCLI prompt, remove the bad uuid with the rmr command for each path that you see the bad uuid existing. 

sample Delete is below

rmr /servers/<<UUID>>

Verification : 

/opt/apigee4/contrib/zk-tree.sh > tree-after.txt

1. Search for all deleted UUIDs in the output file