Exchange 2010 to 2013 public folder migration

I am having issues in a large organization with public folder migration. The issue is that they fail to migrate because of spaces in the "mailnickname" attribute. There are over 5000 folders total so manually removing all the spaces in the names is out of the question. I attempted to use a script to enumerate all of the issues to replace the invalid characters and it fails because of the output is too large. Anyone have some other method to manage the "mailnickname"?

[PS] C:\PFmigration>$pfs= Get-publicfolder "\" -recurse | where {$_.MailEnabled -eq "True"} | Get-MailPublicFolder | whe
re {$_.alias -like `* *' -or $_.alias -like `*,*'}
Sending data to a remote command failed with the following error message: The WinRM client sent a request to the remote
 WS-Management service and got a response saying the request was too large. For more information, see the about_Remote_
Troubleshooting Help topic.
    + CategoryInfo          : OperationStopped: (System.Manageme...pressionSyncJob:PSInvokeExpressionSyncJob) [], PSRe
   motingTransportException
    + FullyQualifiedErrorId : JobFailure

Invoke-Command : Cannot write input as there are no more running pipelines
At C:\Users\exch13\AppData\Roaming\Microsoft\Exchange\RemotePowerShell\mail.xxxxxxxx.local\mail.xxxxxxxx.local.ps
m1:15587 char:29
+             $scriptCmd = { & <<<<  $script:InvokeCommand `
    + CategoryInfo          : InvalidOperation: (:) [Invoke-Command], PSInvalidOperationException
    + FullyQualifiedErrorId : NoMoreInputWrite,Microsoft.PowerShell.Commands.InvokeCommandCommand