Strip Shortcodes

Hello
I’m having just a little problem with my wordpress theme. When I make a post, the preview text is displayed containing the [caption] shortcode. I’d really like to remove this. I know you can use <?php strip_shortcodes( $content ); ?> to remove shortcodes, but I’m very bad at Php and can’t get it to work in my theme.

My theme contains this:

# Removes tags and trailing dots from excerpt
function dp_clean($excerpt, $substr=0) {
	$string = strip_tags(str_replace('[...]', '...', $excerpt));
	if ($substr>0) {
		$string = substr($string, 0, $substr);
	}
	return $string;
}

I’m not sure how any of it works, but I need to include strip_shortcodes() in this function(I think).

Any help is appreciated. Thank You!