Removing/Disabling specific scrip and styles from loading in header

Hi,

I have a little problem trying to remove some script and styles from the header. I have a few plugins and am trying to combine all the styles and some of the javascript to clean the header and speed the site up a little. Problem is the conventional way doesn't seem to work.

I've tried the inserting the following in functions.php but to no result.
I'm just wondering what and where I should be inserting to remove certain script and styles.