I've been modifying a skin, but I can't seem to remove it. I've updated the zip in the skins folder but I assume iGo unpacks it when it loads and because of this, I can't seem to get rid of it. I've deleted the save folder.

Any advice?

Thanks

Set the default skin back in settings. Close the program. Check in the save folder what skin is saved as being used. If it is the default, it should be, delete the skin in the content/skin folder.
And when you delete the skin before restoring the default, the program should use the default skin too and save this after closing.