How to exclude certain portfolios from a loop

so I am thinking your $arg would be:

$args = array(
    'numberposts' => $portfolio_items,
    'order' => $portfolio_sort,
    'orderby' => 'date',
    'post_type' => array('portfolios'),
    'offset' => $offset,
    'exclude'         => '1,2',
);

And that would exclude post 1 and 2.

But a better option that you should do, is to just create a featured category for your work. And then only display the posts that are in the featured category. That way you wouldn’t have to hand type in post ID’s everytime you want them excluded in your loop.