下面是一个示例代码，演示如何使用PowerShell删除活动目录中的旧用户帐户：

# 导入Active Directory模块
Import-Module ActiveDirectory

# 设置旧账户的最后登录日期阈值（例如，删除已经超过90天没有登录的帐户）
$lastLoginThreshold = (Get-Date).AddDays(-90)

# 获取所有旧账户
$oldAccounts = Get-ADUser -Filter {LastLogonDate -lt $lastLoginThreshold} -Properties LastLogonDate

# 循环遍历每个旧账户并删除
foreach ($account in $oldAccounts) {
    # 显示要删除的帐户信息
    Write-Host "Deleting user account: $($account.Name) ($($account.SamAccountName))"
    
    # 删除帐户
    Remove-ADUser -Identity $account -Confirm:$false
    
    # 检查是否成功删除帐户
    if (-not (Get-ADUser -Filter {SamAccountName -eq $account.SamAccountName})) {
        Write-Host "User account $($account.Name) ($($account.SamAccountName)) has been successfully deleted."
    } else {
        Write-Host "Failed to delete user account $($account.Name) ($($account.SamAccountName))."
    }
}

请注意，这是一个简化的示例，仅删除超过指定日期的帐户。根据实际需求，您可能需要根据其他条件过滤帐户，例如特定的部门或禁用状态等。