What it means by "With .. you can specify a range of characters." is a range of characters such as 1 to 9, or A to C, etc (1..9, or A..C, etc). For the basic characters you wish stripped, simply list one right after another, such as " -" or " \t_" etc. Nothing to seperate them, PHP will look at the characters one by one unless it sees .. to designate a range.
-m