I gave you the exact code you needed and told you what do do with it, however if you are not wanting to keep the script in the directory in question then something like this is what you want. There are four lines only, do not add anything else.
$SrceFldr = "C:\WebSphere\AppServer\profiles\Dmgr\config\temp\download\cells\MCHODR01Cell01\applications\ClinicalReportServerEAR-PROD.ear"
$FrntName = "ClinicalReportServerEAR-PROD"
$1HourOld = [DateTime]::Now.AddHours(-1)
Get-ChildItem "$SrceFldr\$FrntName*.tmp" | where-object {$_.LastWriteTime -lt $1HourOld} | Remove-Item
Depending upon your source files it may be preferable to change 'LastWrite' to 'Creation'