If you want to dump large lists quickly you can use batch delete script mentioend below.  Deleing items one by one in loop will take a lot of time.  Even if you delete the items they will get stuck in site collection recyle bin.  You can modify the script as needed.

Add-PSSnapin Microsoft.SharePoint.powerShell -ErrorAction SilentlyContinue 

$sitecollectionUrl = https://portal.contoso.com
$siteCollection = New-Object Microsoft.SharePoint.SPSite($sitecollectionUrl)
$web = $siteCollection.OpenWeb('Web') 

$list = $web.Lists["Logging List"] 

write-host("Logging List has : $list.ItemCount Items.") -ForegroundColor Yellow
write-host("Recyle Bin has : $siteCollection.RecycleBin.Count Items.") -ForegroundColor Yellow 

$itemCount = 0;
$listId = $list.ID;
[System.Text.StringBuilder]$batchXml = New-Object "System.Text.StringBuilder";
$batchXml.Append("<?xml version=`"1.0`" encoding=`"UTF-8`"?><Batch>");
$command = [System.String]::Format( "<Method><SetList>{0}</SetList><SetVar Name=`"ID`">{1}</SetVar><SetVar Name=`"Cmd`">Delete</SetVar></Method>", $listId, "{0}" ); 

$listItems = $list.Items
foreach ($item in $listItems)
{
    if($item -ne $null){$batchXml.Append([System.String]::Format($command, $item.ID.ToString())) | Out-Null;$itemCount++;}
} 

$batchXml.Append("</Batch>");
$itemCount; 

$web.ProcessBatchData($batchXml.ToString()) | Out-Null;Write-Host("Starting to Clear Site Collection Recyle Bin: $siteCollection.RecycleBin.Count") -ForegroundColor Yellow 
$siteCollection.RecycleBin.DeleteAll();
Write-Host("Cleared Log List and Site Collection Recyle Bin.")
$web.Dispose()
$siteCollection.Dispose()