Where Can I find a (clean) list of app-id of my steam-library ?

If a user has a public profile, you can add "games?xml=1" at the end of the url to get this list.
In your case: http://steamcommunity.com/id/Sighery/games?xml=1

Then you could use the console of your browser to get the wanted array.
If you require only appIDs

var list = document.getElementsByTagName('appID');
var requiredArray = [];
for(var i=0; i<list.length; i++)
  requiredArray.push(list[i].textContent);

Edit: you could also give a look here