Remove Sky Noon Beta Key from Library?

I get this from alienwarearena website,then i try remove it in the ways you say but is can't at me because when i go support - it not give me option for remove this game (all other i can remove) also in licenses list not have remove button too.
edit:
i forget to say thank you btw for the reply and try help.

Thanks man, it worked. But I removed another game called Batalj. It also did not have a support page like Sky noon. I all did was to find the appid and replaced appid with the one in the link provided.

i do this you write and it work is remove game from my library,thank you,i add you my wishlist i hope if\when i make new game giveaway you can enter.

I just tried this and it worked for me. Thanks Sooth :)