songs not playing in playlist issues

ive somehow managed to block certain songs from playing on my playlists. i can view them still but they are faded out and wont add to play next etc. ive tried to see if theyve been 'hidden' on i-cloud but cannot access the un-hide option on my itunes account. my account is linked to my mac my i-pad and an old desktop. Can see them all listed however the mac and i-pad 'remove' buttons are faded but the desk top is highlighted. thats the only one i would like to remove as its back in South Africa and im UK based. too **** afraid to move but need my tunes...whats a dummy todo? any help greatly appreciated.

Cass