Skype use a lot of filters they filter ur mac address/IP. Other thing is when u card skype it wont last for long as they block ur acc saying its fraudulent, main thing is when u card it using socks it'l go through but when u start using it either u use it with your own ISP (which is stupid) or u use VPN (if u got then fresh then ur acc will last for some time but if not then 30min ur acc is blocked) non vbv bins work quite good for skype.
CA bins go quite gd2.