How can I delete closed giveaway?

Well then it's probably a good thing you deleted the giveaway because beta keys aren't allowed.

Also I still don't understand why you'd want to delete a months-old already-deleted giveaway.

Once you made a giveaway, it will remain in your account history forever. Why would anyone want to remove it anyway?

I certainly did not. Until Compassnorth's post, I had no idea what was happening.

What do you mean?

I guess since you reported it yourself and asked for the situation to be corrected, they might let you off without a suspension.

It took some time for me to understand why you were trying to get them deleted. I thought at first that you just wanted to hide the fact that you broke the rules in the past. Now I'm guessing that you were mostly trying to make things right.