Remove a node from Failover Cluster We had 5 SQL Server 2012 servers configured with AlwaysOn.
A few days ago we dismissed 2 of them, we removed them from the availability group and then stopped SQL services. We need to reuse these servers for other purposes.

I need to know how to remove them also from the Windows Failover Cluster on which AlwaysOn is based.

Is it enough to click on the nodes and press "stop cluster service" and then "evict"?

Or there is something to do also with the SQL server installation?

Please note that the two servers will be formatted, so local SQL installation can be destroyed.
Removing SQL Server from failover cluster - you have to run the setup.exe and in maintenance you have to select remove node.

Then removing the node from windows cluster, I would suggest you use PowerShell 

Remove-ClusterNode –Name node4 #change your node name here 


  The Remove-ClusterNode cmdlet removes a node from a failover cluster. After the node is removed, the node no longer functions as part of the cluster unless the node is added back to the cluster. Removing a node is also called evicting a node from the cluster.


The above commmand will ask your confirmation if you want to really evict the node or not -- unless you use use /force switch.