Eh? Do you mean when you watch something you've recorded you want it to skip the adverts automatically? Can't be done. Sky aren't that stupid, they make a lot of money from ads, those advertisers wouldn't be happy if Sky allowed you to bypass them altogether.
Or are you refering to the annoying little messeges like "remind me" etc that pop up in the top corner of the picture from time to time? These can be removed by hitting "backup" on the remote when they appear.