Remove files when first two characters are ZZ
Get all objects (including hidden, recursively) from a path with names starting with 'zz', filter out directory objects and delete the items.
Get-ChildItem <path> -Recurse -Force -Filter zz* | Where-Object {!$_.PSIsContainer} | Remove-Item
get-childitem zz* | where-object {$_ -cmatch "^(zz|ZZ)"} | foreach-item {remove-item $_.fullname}