If you cant disable / remove the apps from the search heads then this means it was deployed from the deployment server. Open "forwarder management" from the deployment server and remove it from the server class there.
FYI, you shouldnt use the Deployment Server for search head apps if you're using a SH Cluster. If you have a SHC, then your apps will be found on the search head cluster deployer under /etc/shcluster/apps. To remove from SHC, you'lll delete the app folder from /etc/shcluster/apps on the SHC deployer and the push the shcluster bundle again.
http://docs.splunk.com/Documentation/Splunk/6.2.2/DistSearch/PropagateSHCconfigurationchanges
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