Write module used hook_cron process delele node content type !

mymodule.php

function MYMODULE_cron() {
    $query = new EntityFieldQuery;

    $result = $query->entityCondition('entity_type', 'node')
        ->propertyCondition('type', 'YOUR-CONTENT-TYPE')
        ->execute();

    if (isset($result['node']) && count($result['node'])) {

        $node_ids = array_keys($result['node']);

        node_delete_multiple($node_ids);
    }
}