Removing Unused Service Application App Pools Using Power Shell

1.  Log into your Central Administration server

2.  Bring up SharePoint 2010 Management Shell (PowerShell) using Admin rights

3.  To list all SharePoint 2010 Service Application App Pools run this PowerShell cmdlt

Get-SPServiceApplicationPool

4.  To remove the Service Application App Pools simply run this PowerShell cmdlt
Remove-SPServiceApplicationPool “[Name of Service Application App Pool]“

5.  You will be promoted to confirm:
Are you sure you want to perform this action?
Performing operation “Remove-SPServiceApplicationPool” on Target “Name of Service Application Pool”
[Y] Yes [A]Yes to All [N] No [L] No to All [S] Suspend [?] Help
<default is “Y”>:

6.  After selecting Y for Yes, you can now double check to make sure the Service Application App Pool was indeed removed by re-running the Get-SPServiceApplicationPool cmdlt

7.  You should no longer see the Service Application App Pool.

8.  Now you can go back to Central Administration and attempt to create the Service Application App Pool using the same name used previously.