If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.
You may also want to use the oc get secrets command to display the secrets that have already been created.
oc get secrets NAME TYPE DATA AGE mysecret1 Opaque 1 133d mysecret2 Opaque 1 133d mysecret3 Opaque 1 127d
The oc delete secret command followed by the name of a secret can be used to delete a secret.
oc delete secret mysecret1
If the secret is successfully deleted, the following will be displayed.
secret "mysecret1" deleted